26622228 Lawn Boy Service Manual 1950 88 Complete

This Service Manual i s Dedicated to -- FIRST - Lawn-Boy Service Accounts everywhere. It

has been designed for your use-primarily.

SECOND - Our Lawn-Boy Retailers. If they will use it, all our jobs will be easier.

THIRD - Our Consumer. Without him this bookwould not be possible.

The objective of LAWN-BOY, A PRODUCT GROUP OF OUT- BOARD MARINE CORPORATION GALESBURG, ILLINOIS is to provide quality lawn and garden equipment to its customers at as reasonable a price as possible. There will be no compromise on quality of product, or on SERVICE behind our products.

THE RIGHT WAY IS THE ONLY WAY TO DO ANY- THING. FAIRNESS AND HONESTY TO EVERYONE WITH WHOM WE DO BUSINESS IS OUR CREED.

With these as our standards, we (you and Lawn-Boy) will have continuing success, year after year.

SAFETY

THE PURPOSE OF SAFETY SYMBOLS IS TO ATTRACT YOUR ATTENTION TO POSSIBLE DANGERS. THE SYM- BOLS, AND THE EXPLANATIONS WITH THEM, DESERVE YOUR CAREFUL ATTENTION AND UNDERSTANDING. SAFETY WARNINGS DO NOT BY THEMSELVES ELIMI- NATE ANY DANGER; THE INSTRUCTIONS OR WARNINGS

DENT PREVENTION MEASURES.

Symbol Meaning

THEY GIVE ARE NOT SUBSTITUTES FOR PROPER ACCI-

SAFETY FAILURE TO OBEY A SAFETY WARNING WARNING MAY RESULT IN IN-

JURY TO YOU OR TO OTHERS.

ADVISES YOU OF INFORMATION OR INSTRUCTIONS VITAL TO THE OPERATION OR MAINTENANCE OF YOUR EQUIPMENT.

Over the past 60 years the American consumer has been offered many kinds of luxury items, conveniences, labor saving devices, and recreation and sports equipment. The ingenuity of the inventor, combined with engineering and manufacturing know-how, has provided the consumer with many things he would not even have dreamed before. That’s PROGRESS.

Today, service and repair shops “never had it so good.” Many of these luxuries and conveniences are mechanical. They have become necessities. As a result, the good service repair shop has started to build and expand. And, the number of shops has increased terrifically in the past few years.

New discoveries are being made every day. Inventions are turned into

foreword products ready for the. consumer in ever increasing quantities year after year. So, the service business should be good for many, many. years to come. And, manufacturers are becoming increasingly aware of the consumer as the “guy who pays for everything.” He is the one they have to keep happy.

Quality manufacturers realize that the closest link they have with the consumer is that which exists through their service dealers. That’s why many manufacturers, including Lawn-Boy, have based their over all service programs on the service dealer level, planning the entire program upward from there. Years ago we started our Lawn-Boy service program by planning the easiest and simplest methods of service procedure and policy, including the no parts returned to the factory unless requested - standard per hour warranty labor rate - fair and reasonable time limits established for various repair jobs with reimbursement of service ‘dealer costs for parts used in

warranty repairs. We will continue to do everything we can to make servicing accounts work easier and, if possible, more profitable.

There will be a tremendous opportunity, in our opinion, in the service repair business during the next 10 to 15 years. There will be many new mechanical labor saving devices produced which cannot help but demand more, better, and faster repair shop service throughout the country. Lawn-Boy will continue to develop new products and improve design of all their lawn and gardening products from year to year.

THE OPPORTUNITY IS YOURS. IT’S UP TO Y o u .

THE PURPOSE OF SAFETY SYMBOLS IS TO ATTRACT YOUR ATTENTION TO POSSIBLE DANGERS. THE SYMBOLS, AND THE EXPLA- NATIONS WITH THEM, DESERVE YOUR CAREFUL ATTENTlON AND UNDERSTAND- ING. SAFETY WARNINGS DO NOT BY THEM- SELVES ELIMINATE ANY DANGER; THE IN-

ARE NOT SUBSTITUTES FOR PROPER ACCI- STRUCTIONS OR WARNINGS THEY GIVE

DENT PREVENTION MEASURES. Symbol Meaning

SAFETY Failure to obey a safety warning may result in injury to you or to others. Advises you of information or in-

NOTE: structions vital to the operation or maintenance of your equipment.

This mower is designed and intended for the purpose of mowing (cutting) grass and, when specially equipped with a grass bag, for bagging cut grass. Any use for purposes other than those noted above could prove dangerous to user or bystanders.

SAFETY WARNINGS Prevent accidents. Use the following practices for operating your mower safely. These warnings apply to all rotary, gasoline

recommended by LAWN-BOY and the Outdoor Power Equip- engine powered mowers, regardless of manufacturer. They are

ment Institute. Inc., Washington, D.C.

CLEAR THE AREA Clean the lawn of sticks, stones, wire, etc. They can be picked up and hurled great distances by the blade. Mow only in cleaned ares. Keep children and pets away from vicinity of mower as you would any cutting machinery.

WEAR PROPER ATTIRE Don't wear loose fitting clothing. Provide some external protection for yourself by means of long, heavy denim trousers and heavy shoes. Never mow when barefoot or wearing open sandals. Safety shoes are recommended.

CHECK THE MOWER BEFORE USE Check all nuts, bolts and fasteners for tightness, especially the blade nut (torque blade nut 45-50 ft. lbs.). Disconnect spark plug lead (Electric start models; also disconnect battery connections) before check. Keep all guards in place at all times. Keep either cover plate or grass catcher chute with bag in place and secure a t all times. Check grass or leaf bags for wear or deterioration. Replace bag if necessary. Have a competent serviceman make a thorough inspection of your mower a t least once a year.

HANDLE FUEL PROPERLY Gasoline is extremely flammable and highly explosive under certain conditions. Always stop engine, and do not smoke or allow open flames or spark when mixing fuel or refueling. Do not fill fuel tank while engine is hot or running. Spilling fuel on a hot engine may cause a fire or explosion. To prevent possible explosion or ignition of vaporized fuel, do not store mower with fuel in tank or carburetor in enclosure with open flame. (Example: Furnace or water heater pilot light.) Always store or transport mower with fuel shut-off valve in the "OFF position.

Fill tank outdoors. Wipe up spilled gasoline. Replace cap securely. Use an approved safety container to handle and store gas. Keep engine free from accumulations of grass, leaves or excessive grease. These combustible materials could result in a fire. Never start or run the engine inside where exhaust fumes can collect. Carbon monoxide present in the exhaust is an odorless and deadly gas. KNOW YOUR CONTROLS Learn how to stop the engine quickly. Be sure the control handle is in "NEUTRAL" position (to the rear) before starting or stopping self-ropelled models.

START AND MOW WITH CARE Never allow anyone to operate your mower without complete instructions. Teach all safety rules and operating instructions to all users. DO NOT ALLOW CHILDREN TO OPERATE MOWER.

Don't start the engine until you are ready to mow. Be sure mower will not tip or roll during starting operation. When starting engine, place one foot on top of blade housing s designated with heel off the ground to aid stability. Never stand in front of self-propelled mowers. Keep clear of discharge opening. Keep hands and feet away from moving parts. Never place hands or feet under the mower while blade is turning. Stop the engine and make sure the blade has come to a complete stop and the spark plug wire is disconnected, (Electric start models; disconnect battery connections) before attempting to dean or unclog the catcher assembly or discharge chute. Always push, never pull, a mower with the engine running. Mow across face of slopes. Do not mow excessively steep slopes. Control direction of mower by hand pressure on the handle, not foot pressure on the mower housing. Do not lag behind or let mower pull you. Keep a firm hold on the handle and walk, never run with mower. Mow in daylight or good artificial light. Never operate equipment in wet grass. Always be sure of your footing. Stop engine before changing or emptying catcher bag, pushing mower across walks, drives, roads or before leaving operating position, even for a moment. I f operating mower on uneven or rough ground, be especially careful. Front of mower may drop lower than normal, and hidden objects may be thrown by blade. Keep all four wheels on the ground when mowing. I f mower is tipped while blade is turning, blade is exposed and accidents can occur. Avoid striking trees, walls, curbs or other solid objects with mower. Never deliberately mow over any object. Exercise special care when mowing around objects to prevent the blade striking them. If an object is struck, or mower starts to vibrate. stop engine immediately, remove spark plug wire (Electric start models; also disconnect battery connections) and examine mower for damage. Replace damaged parts before restarting and operating mower. MAKE ADJUSTMENTS CAREFULLY_ Do not overspeed engine or alter governor settings. Excess speed Is dangerous and shortens mower life. Stand to one side and keep feet and hands clear while making carburetor adjustments. Height adjustments should be made only after engine and blade are stopped. Disconnect spark plug lead (Electric start models; also disconnect battery connections) prlor to performing service on engine or mower. Keep lead away from plug. On self-propelled models be sure control is in "NEUTRAL" position. Never rotate blade with hand or foot without first removing spark plug wire (Electric start models; also disconnect battery connections) to prevent starting.

REMOVE KEYS WHEN STORING Electric start mowers cannot be started, even manually, with key removed.

REPLACEMENT PARTS When replacement p a r t s are required, use genuine OMC parts or parts with equivalent characteristics including type, strength, and material. Failure to do so may result in product malfunction and possible injury to the operator and/or bystanders. IT'S UP TO YOU. A POWER MOWER IS NO SAFER THAN ITS OPERATOR.

SECTION 1 MOWER HISTORY TWO CYCLE THEORY-

DEVELOPMENT OF THE AMERICAN POWER MOWER

The following information on the history of the development of power mowing in America has been col- lected from the most reliable sources we could find.

1890 - This "One Horsepower" Henderson Mower Was Popular. Similar to First Patented Mowers.

The first mechanical mower of which we have any record was patented in England in 1830 by a Mr. Edwin Budding of Stroud, Glou- cestershire. This mower moved on a massive iron roller and featured a reel blade that worked against a parallel bedplate. The Budding mower gave us the still-popular principle of the reel-cutting blade. 1500 of these were produced between 1833 and 1859. Suc- cessors to this company are still in business, under the name of Lawn Mower Works.

The first power was added in 1842, when a Mr. Shanks of "Shanks' Mare" fame patented a Budding-type horse-drawn mower, In 1859 a mower using chain drive instead of the Budding gear drive was patented - the Silens Messer mower.

The first line of reasonably moderate-priced mowers was brought out by the firm of Ransome, Sims and Jeffries, Ltd. in the 1860's. These mowers were of light construction and produced in a number of sizes with varying features.

In , 1878, the Pennsylvania Mower Company patented a side-wheel machine that was driven by' a train of gearing instead of internal gear ring and pinion.

The first gasoline powered lawn mower was patented by Mr. Edward Ransome in 1902, and the first successful attempt to market a gasoline powered mower was made by the Thomas Green firm in 1904.

The electric power mower made its appearance in the early 1920's and rapidly gained wide popularity. The Ransome firm also mass-produced an electric mower several years later which featured headlights for night mowing.

Following World War I, mass production and the general awakening of the American in- dustrial giant brought forth a host of power mower and hand mower manufacturers. From 1918 to 1925 millions of the familiar type hand-push reel mowers were made by scores of manufacturers in the U.S. and abroad. By 1925, however, the gasoline- powered reel mower began to take a bigger and bigger share of the market. For example: in 1924, 880,000 hand-push mowers retailing for $7,000,000 were sold in the U.S. The same year, 5,000 reel-type power mowers were sold for $1,250,000.

1917 - Power Mowers of This Type Were 1920's - One of the First Rotary Power

Toolbox. the Belt Drive. . Becoming Popular. Equipped Complete with Mowers, Produced in the Late 20's. Note

1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

Toward the middle of the 1930's the rotary power mower, featuring a horizontally-mounted cutting blade, began to appear on the American home scene. This was the first and most significant advance in a century of lawn mowing.

Since World War II there have been great strides in the development of power mowers. The rotary has become increasingly popular; and in 1958 approximately 90% of the power mowers sold were rotaries, either self-propelled or push-propelled.

Lawn-Roy became the country's first Production-line manufacturers of complete power mowers, including engines, in the early 1950's when Outboard Marine bought out the Roto Power Mower Company of Kansas City, Missouri, one of the very first rotary power manufacturers.

Power mower sales in 1971 exceeded 5,500,000 units. The walk-behind rotary accounted for 4,700,000, o r 85% of all power mower sales according to the Outdoor Power Equipment Insti- tute. About 80% of the 1971 sales were for the replacement of the 38,000,000 power mowers currently in use in the United States. Sales of rider mowers and lawn tractors have grown to over 800,000 units annually.

Lawn and garden business is booming and will continue to boom. Saturation? . . . it will HELP, NOT HURT, the quality manufacturer.

1959 - The New Lawn-Boy QUIETFLITE 1934 - The 1934 "Lawn-Boy" was Manufac- ushered in the "Golden Age of Power Mow- tured by Evinrude. Self-propelled Chain ing." Its moving and working parts a re Drive Reel Type. completely Sealed and Insulated. QUIET-

FLITE in 1959 was the Last Word in Modern Quiet Power Mower Development.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . , . 1-3

Thru the years Lawn-Boy has continued to improve in design and performance- of Lawn-Boy products. This is one reason why Lawn-Boy is one of the world leaders in the industry. Lawn-Boy is one of the few manufacturers that offers a complete choice of models designed to fit all mowing requirements. From the apartment dweller to the estate owner Lawn-Boy offers a choice to satisfy all lawn and garden requirements.

Tests have shown the Lawn-Boy D-400 Ser- ies, 2 Cycle Engine, to be one of the best engines available. The heart of your mower is the engine and the D-400 Series is designed to offer years of dependable service.

1972 Lawn-Boy introduced its first Solid State (CD) D-600 Series engine. Available with manual or electric start - self-propelled or push propelled type models. The solid state ignition system has no moving parts, is completely enclosed reducing ignition failure while producing up to 30,000 volts. No points, coil or condenser to replace, offering longer spark plug life. The all new carburetor used on the D-600 Series engine is completely automatic. No adjustments other than an atmospheric pressure adjustment is required. A new primer system forces compressed air into the float chamber which forces fuel into the carburetor venturi. This method of priming is effective and consequently, one prime is usually sufficient to start the engine. The larger muffler design reduces noise and exhaust down into the turf.


Lawn-Boy developed the revolutionary CORDLESS ELECTRIC MOWER - powered by 36 volts this compact mower contains all the engineering "know-how" and safety features of gasoline operated mowers. Exces- sive noise and exhaust fumes are eliminated. One more FIRST for Lawn-Boy.

In the future Lawn-Boy will continue to improve to offer you, the dealer, and your customers the best product available.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . 1-5

THE NEW GENERATION

The new generation series of Lawn-Boy mowers combines 68 years of 2-cycle technology with advanced engineering and manufacturing procedures. The final result is an all new look from the "grass up." 21 fewer parts, less weight, and introducing an all NEW "F" series Lawn-Boy engine which produces 20 to 30% more usable power.

Lawn-Boy has retained and refined all the outstanding features that have made us famous.

Easy fingertip starting - a reduced 4 to 1 gear ratio resulting in the easiest starting mower in Lawn-Boy's history.

Quiet operation - featuring a new exhaust system. The welded muffler assembly contains an additional baffle and muffler tube. Designed as a one-piece assembly secured to the mower with only three screws.

Super vacuum action - the design of the mower housing and famous durable Lawn-Boy high lift blade has been improved to discharge clippings into the rear of the grass bag -- this creates a well manicured mowing appearance. Also added under the deck is a crankshaft support located approximately 2 inches above the blade to provide additional protection for the crankshaft and crankcase.

The new generation began in the summer of-1972. WHY?

1. Contain fewer parts.

2. Design a new engine which develops more power at lower RPMS which meets or exceeds OPEI safety standards.

1973: First engineering prototype "F" engine run. 1974: New fuel and governor system developed and

1975: In May, first factory "die cast" engine tested. 1975: In October, first units released for extensive field

1977: In October, full factory production began after

tested.

testing.

- 2 years of thorough and extensive testing.

This is not the end -- rather, the beginning of a NEW GENERATION for us the manufacturer and you the service dealer. 1983: In July, after 9 years of research and development,

Lawn-Boy started producing compliance lawn mowers that featured two different blade stopping systems.

One is the blade, brake, clutch (BBC) system which stops the blade within 3 seconds after the operator releases the bail. The engine continues to run with this system.

The other is a flywheel brake system which stops both the blade and engine within 3 seconds after. the operator releases the bail.

THE NEW GENERATION "F" SERIES 2 CYCLE

UNITIZED POWERHEAD

An automated, computer-controlled machine manufactures two pieces into

a cylinder block assembly that has uniformity

and precision.

PRESSURE-BACK PISTON RING

Minimizes compression blowby- to increase usable power,

improve fuel economy and aid starting ease.

NO-TUNE-UP ELECTRONIC IGNITION \

I

ENGINE

FRICTION-REDUCING NEEDLE BEARINGS

The crankshaft, top and bottom, as well as the connecting rod,

are nestled in precision needle bearings, resulting in

free running, smooth operation. Silverplated

bearing liner at the big end of the connecting rod.

I

Lawn-Boy mowers meet or exceed current A.N.S.I. B71. Ib 1977

safety standards for rotary-type mowers. We proudly display

this Outdoor Power Equipment Institute seal on each machine.

\ MORE

USABLE POWER

Displacement is increased from 6.6 to 7.7 cubic inches. This and other improvements

add 20-30% more usable power.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7

PRINCIPLES OF O P E R A T I O N R O T A R Y P O W E R M O W E R S

Rotary mowers are generally designed with On the rotary mower, height of cut is changed four wheels to support a housing on top of by changing the wheel height. The cutting which is mounted the engine, and with the blade is usually attached directly to the en- cutting blade mounted horizontally inside gine shaft, and is generally made of tem- and beneath the housing. pered steel of varying widths. Length of the

cutting blade is determined by the size of The blade is designed to "lift" the grass as the mower housing. it rotates, by creating an upward flow of air. This insures even cutting.

Rotary mowers are capable of cutting level, The housing covers the blade, channeling the clean lawns, as well as rough lawns. They flow of grass out a discharge chute. Ridding are limited in their cutting ability in height the housing of cut grasses is a necessity, of grass (or weeds), only by the amount of in order to eliminate power loss. material to be discharged.

W H A T I S THE DIFFERENCE BETWEEN 2-CYCLE ENGINES? There are four main Differences in the operation of 4-cycle and 2-cycle engines:

POWER - Number of power strokes per crankshaft revolution.

EXHAUST - Method of scavenging burned gases from combustion chamber. LUBRICATION - Method of providing internal moving parts with oil film.

INTAKE - Method of getting fuel vapor to the combustion chamber.

2-CYCLE OPERATION

First Stroke - UP - Piston moves up in cylinder. Piston movement creates vacuum in crankcase. Fuel Entry Reed valve opens. Fuel air vapor enters crankcase. As piston reaches top of cylinder, fuel vapor in cylinder is compressed.

Explosion forces piston down, delivering power.

Second Stroke - DOWN - Fuel entry valve closes. POWER STROKE Exhaust ports open, burned gases escape.

Downward movement of piston creates pressure in crankcase. Intake ports open as piston moves by - Crank- case pressure forces fuel vapor to rush into cylinder. Incoming fuel vapor clears cylinder of a l l burned gases.

NOTE: 2-cycle f i res EACH revolution, requiring only one turn of the crankshaft to complete intake, firing, and exhaust. 2-cycle delivers TWO power strokes while 4-cycle is completing ONE.

4-CYCLE OPERATION

First Stroke - DOWN - INTAKE Piston moves 'down towards the

Intake Valve is Open, Exhaust

Fuel enters compression chamber

crankcase.

Valve Closed.

(cylinder).

Second Stroke - up - COMPRESSION Piston moves up in cylinder Intake and Exhaust valves are

Fuel vapor is being compressed closed.

for igniting.

Third Stroke - DOWN - POWER STROKE Fourth Stroke - UP - EXHAUST P i s t o n moves down after spark ig- Piston moves up.

nites and explodes fuel vapor, fur- Exhaust valve is open. nishing power output. Burned vapors are forced out of

cylinder.

NOTE: NUMBER OF MOVING PARTS IN 4-cycle operation. 4-cycle fires every fourth stroke, requiring TWO complete turns of the crankshaft to complete the four operations.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9

DESIGN APPLICATION

4-CYCLE LUBRICATION 2-CYCLE LUBRICATION

The 4-cycle engine requires a separate system of lubrication, with an oil sump that must be kept full and operated on a fairly level surface to prevent lack of lubrication to internal moving parts. The 4-cycle system includes an oil reservoir, slinger or oil pump (which are ineffective if the mower engine is run with a low oil supply or tilted to an extreme angle), often resulting in damage to the engine.

The 2-cycle engine is always lubricated as long as there is a fuel mixture in the fuel tank. No attention to oil level is required, as the oil is pre-mixed with the fuel. The engine is kept lubricated regardless of angle of operation. The oil, suspended in the fuel vapor, adheres to the surfaces of all the moving parts, keeping them continually coated with a film of oil.

MAINTENANCE Ease of maintenance increases with 2-cycle operation, because: (1) There are fewer moving parts to wear. (2) 2-cycle lubrication reaches every moving part every stroke, and the oil is always fresh and clean. (3) Clean lubrication means longer life for moving parts.

e

MOVING PARTS - 4-CYCLE ENGINE MOVING PARTS - 2-CYCLE ENGINE

Include timing gears, cam shaft, intake and There are only THREE major moving parts exhaust valves, slinger or oil pump, springs. in the 2-cycle engine. These can be repaired All are additional parts required for 4-cycle o r replaced with the simplest of working engines. These create more friction, more tools. No valves to grind, cam shafts, push wear, and require more equipment, extra rods, timing gears, valve springs, etc. to time and materials for overhaul. adjust or replace.

THE 2-CYCLE ENGINE IS EASIER TO CARE FOR AND TO REPAIR

1-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

Using This Manual - Section 2

Page 1 of 23

This manual applies directly to Lawn-Boy products produced between 1950 and 1988. It isalso used for servicing the F Series engine used on select Lawn-Boy walk mowers through2000. It contains service information for Lawn-Boy C, D, and F Series 2-cycle engines; PistonPower Products (Ryobi) 2-cycle trimmer engines; and related drive train and chassisinformation.

This manual, form 492-4608, is several hundred pages long. For ease of use in electronicform, this manual has been broken down into numerous smaller files. Please ensure the fileyou are viewing is the correct one for the machine being serviced. The list below gives modelnumber, model year, serial range, and engine manufacturer/model information to assist you inselecting service information. You may also find the information in Section 16 helpful (QuickReference Guide, Engine and Torque Specs).

Model Year Serial Range Engine Manuafacturer Engine Model Number0292 1980 000000001-099999999 Lawn-Boy F2100292A 1981 100000001-199999999 Lawn-Boy F2110292B 1982 A00000001-A99999999 Lawn-Boy F2110296 1983 B00000001-B99999999 Lawn-Boy F1000363 1984 C00000001-C99999999 Briggs & Stratton 110902-0542-020392 1980 000000001-099999999 Lawn-Boy F2500392A 1981 100000001-199999999 Lawn-Boy F2510392B 1982 A00000001-A99999999 Lawn-Boy F2510393 1982 A00000001-A99999999 Briggs & Stratton 110908-0542-020394 1982 A00000001-A99999999 Briggs & Stratton 92908-0164-020395 1982 A00000001-A99999999 Briggs & Stratton 110908-0542-020396 1983 B00000001-B99999999 Lawn-Boy F0397 1983 B00000001-B99999999 Briggs & Stratton 110902-0542-020399 1983 B00000001-B99999999 Briggs & Stratton 92908-0164-020425A 1985 D00000001-D99999999 Briggs & Stratton 110702-3186-010426A 1985 D00000001-D99999999 Briggs & Stratton 110702-3186-010427 1985 D00000001-D99999999 Briggs & Stratton 110702-3186-011010 1961 100000001-199999999 Lawn-Boy C711010 1962 200000001-299999999 Lawn-Boy C711011 1963 300000001-399999999 Lawn-Boy C741011 1964 400000001-499999999 Lawn-Boy C741012 1965 500000001-599999999 Lawn-Boy C741012 1966 600000001-699999999 Lawn-Boy C741013 1967 700000001-799999999 Lawn-Boy D4601013 1968 800000001-899999999 Lawn-Boy D4601013 1969 900000001-999999999 Lawn-Boy D4601014 1968 800000001-899999999 Lawn-Boy D4611014 1969 900000001-999999999 Lawn-Boy D4611015 1970 000000001-099999999 Lawn-Boy D4621015 1971 100000001-199999999 Lawn-Boy D4621015 1972 200000001-299999999 Lawn-Boy D4621015 1973 300000001-399999999 Lawn-Boy D4621015 1974 400000001-499999999 Lawn-Boy D462


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Model Year Serial Range Engine Manuafacturer Engine Model Number10400 1993 3900001-3999999 Lawn-Boy F10400 1994 4900001-4999999 Lawn-Boy F10400 1995 5900001-5999999 Lawn-Boy F10401 1996 6900001-6999999 Lawn-Boy F10401 1997 7900001-7999999 Lawn-Boy F10401C 1998 8900001-8999999 Lawn-Boy F10401C 1999 9900001-9999999 Lawn-Boy F10401C 2000 200000001-200999999 Lawn-Boy F10415 1993 3900001-3999999 Lawn-Boy F10415 1994 4900001-4999999 Lawn-Boy F10415 1995 5900001-5999999 Lawn-Boy F10420 1993 3900001-3999999 Lawn-Boy F10420 1994 4900001-4999999 Lawn-Boy F10422 1996 6900001-6999999 Lawn-Boy F10422 1997 7900001-7999999 Lawn-Boy F10515 1993 3900001-3999999 Lawn-Boy F10515 1994 4900001-4999999 Lawn-Boy F10515 1995 5900001-5999999 Lawn-Boy F10518 1996 6900001-6999999 Lawn-Boy F10518 1997 7900001-7999999 Lawn-Boy F10520 1993 39000001-39999999 Lawn-Boy F10520 1994 4900001-4999999 Lawn-Boy F10520 1995 5900001-5999999 Lawn-Boy F10523 1996 6900001-6999999 Lawn-Boy F10523 1997 7900001-7999999 Lawn-Boy F10545 1994 4900001-4999999 Lawn-Boy F10545 1995 5900001-5999999 Lawn-Boy F10546 1996 6900001-6999999 Lawn-Boy F10546 1997 7900001-7999999 Lawn-Boy F10600 1993 39000001-39999999 Lawn-Boy F10600 1994 4900001-4999999 Lawn-Boy F10600 1995 59000001-59999999 Lawn-Boy F10601 1996 6900001-6999999 Lawn-Boy F10650 1994 4900001-4999999 Lawn-Boy F10650 1995 59000001-59999999 Lawn-Boy F10651 1996 6900001-6999999 Lawn-Boy F10700 1993 39000001-39999999 Lawn-Boy F10725 1993 39000001-39999999 Lawn-Boy F10735 1993 39000001-39999999 Lawn-Boy F1100 1984 400000001-499999999 Piston Powered Products (Ryobi)1100 1985 500000001-599999999 Piston Powered Products (Ryobi)1100 1986 600000001-699999999 Piston Powered Products (Ryobi)1100 1987 700000001-799999999 Piston Powered Products (Ryobi)1100 1988 800000001-899999999 Piston Powered Products (Ryobi)1100 1989 900000001-999999999 Piston Powered Products (Ryobi)11000 1997 790000001-799999999 Lawn-Boy F11000B 1994 49000001-49999999 Lawn-Boy F


Page 3 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number11000B 1995 59000001-59999999 Lawn-Boy F11000B 1996 69000001-69999999 Lawn-Boy F11001 1997 7900001-7999999 Lawn-Boy F11001B 1996 69000001-69999999 Lawn-Boy F1116 1961 100000001-199999999 Lawn-Boy C721116 1962 200000001-299999999 Lawn-Boy C721116 1963 300000001-399999999 Lawn-Boy C721116 1964 400000001-499999999 Lawn-Boy C721150 1987 700000001-711999999 Piston Powered Products (Ryobi)1150 1987 712000000-799999999 Piston Powered Products (Ryobi)1150 1988 800000001-811999999 Piston Powered Products (Ryobi)1150 1989 812000000-899999999 Piston Powered Products (Ryobi)1150 1989 900000001-999999999 Piston Powered Products (Ryobi)1300 1980 000000001-099999999 Piston Powered Products (Ryobi)1300 1981 100000001-199999999 Piston Powered Products (Ryobi)1330 1980 000000001-099999999 Piston Powered Products (Ryobi)1360 1980 000000001-099999999 Piston Powered Products (Ryobi)1360 1981 100000001-199999999 Piston Powered Products (Ryobi)1400 1983 300000001-399999999 Piston Powered Products (Ryobi)1400 1984 400000001-499999999 Piston Powered Products (Ryobi)1400 1985 500000001-599999999 Piston Powered Products (Ryobi)1400 1986 600000001-699999999 Piston Powered Products (Ryobi)1400C 1985 D00000001-D99999999 Piston Powered Products (Ryobi)1400C 1987 700000001-799999999 Piston Powered Products (Ryobi)1400CL 1986 600000001-611999999 Piston Powered Products (Ryobi)1400CL 1986 612000000-699999999 Piston Powered Products (Ryobi)1400CL 1987 700000001-711999999 Piston Powered Products (Ryobi)1400CL 1987 712000000-799999999 Piston Powered Products (Ryobi)1400CL 1988 800000000-811999999 Piston Powered Products (Ryobi)1400CL 1988 812000000-899999999 Piston Powered Products (Ryobi)1400CL 1989 900000001-999999999 Piston Powered Products (Ryobi)1400CLC 1987 700000001-799999999 Piston Powered Products (Ryobi)1460 1984 400000001-499999999 Piston Powered Products (Ryobi)1460 1985 500000001-599999999 Piston Powered Products (Ryobi)1460 1986 600000001-699999999 Piston Powered Products (Ryobi)1460C 1985 500000001-799999999 Piston Powered Products (Ryobi)1480 1986 600000001-611999999 Piston Powered Products (Ryobi)1480 1986 612000000-699999999 Piston Powered Products (Ryobi)1480 1987 700000001-711999999 Piston Powered Products (Ryobi)1480 1987 712000000-799999999 Piston Powered Products (Ryobi)1480 1988 800000000-811999999 Piston Powered Products (Ryobi)1480 1988 812000000-899999999 Piston Powered Products (Ryobi)1480 1989 900000001-999999999 Piston Powered Products (Ryobi)1480C 1986 600000001-699999999 Piston Powered Products (Ryobi)1480C 1987 700000001-799999999 Piston Powered Products (Ryobi)1490 1985 500000001-599999999 Piston Powered Products (Ryobi)1490C 1986 600000001-699999999 Piston Powered Products (Ryobi)


Page 4 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number1816 1961 100000001-199999999 Lawn-Boy C12AA1817 1962 200000001-299999999 Lawn-Boy C17AA1818 1963 300000001-399999999 Lawn-Boy D470, C18AA1820 1965 500000001-599999999 Lawn-Boy C18AAR, C19AA1820 1966 600000001-699999999 Lawn-Boy C18AAR, C19AA1840 1972 200000001-299999999 Briggs & Stratton 100202-0434-011840 1975 500000001-599999999 Briggs & Stratton 100202-0434-011840A 1973 300000001-399999999 Briggs & Stratton 100202-0434-011840A 1974 400000001-499999999 Briggs & Stratton 100202-0434-011840A 1975 500000001-599999999 Briggs & Stratton 100202-0434-011840A 1976 600000001-699999999 Briggs & Stratton 100202-0434-011850 1979 900000001-999999999 Lawn-Boy D5701851 1980 000000001-099999999 Lawn-Boy D5721871 1980 000000001-099999999 Lawn-Boy D572E1920 1964 400000001-499999999 Lawn-Boy C18AAR, C19AA1921 1965 500000001-599999999 Lawn-Boy C18AAR, C19AA2010 1962 200000001-299999999 Lawn-Boy C812010 1963 300000001-399999999 Lawn-Boy C812010 1964 400000001-499999999 Lawn-Boy C812010 1965 500000001-599999999 Lawn-Boy C8122240 1997 7900001-7999999 Lawn-Boy F22241 1997 7900001-7999999 Lawn-Boy F25574 1974 400000001-499999999 Briggs & Stratton 130902-020725575 1975 500000001-599999999 Briggs & Stratton 130902-02072650 1970 000000001-099999999 Briggs & Stratton 130202-0196-022650 1971 100000001-199999999 Briggs & Stratton 130202-0196-022650A 1972 200000001-299999999 Briggs & Stratton 130202-0237-022650B 1973 300000001-399999999 Briggs & Stratton 130202-0237-022650B 1974 400000001-499999999 Briggs & Stratton 130202-0237-022650B 1975 500000001-599999999 Briggs & Stratton 130202-0237-022680 1970 000000001-099999999 Briggs & Stratton 190402-0171-012680 1971 100000001-199999999 Briggs & Stratton 190402-0171-012680A 1972 200000001-299999999 Briggs & Stratton 190402-0654-022680B 1973 300000001-399999999 Briggs & Stratton 190402-0654-022680B 1974 400000001-499999999 Briggs & Stratton 190402-0751-012680B 1975 500000001-599999999 Briggs & Stratton 190402-0751-012680B 1976 600000001-699999999 Briggs & Stratton 190402-0751-013001 1967 700000001-799999999 Lawn-Boy C783002 1967 700000001-799999999 Lawn-Boy C783002 1968 800000001-899999999 Lawn-Boy C783002 1969 900000001-999999999 Lawn-Boy C783003 1970 000000001-099999999 Lawn-Boy C793003 1971 100000001-199999999 Lawn-Boy C793050 1959 900000001-999999999 Lawn-Boy C703050 1960 000000001-099999999 Lawn-Boy C703050 1961 100000001-199999999 Lawn-Boy C703051 1962 200000001-299999999 Lawn-Boy C73


Page 5 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number3052 1963 3000001-3999999 Lawn-Boy C733052 1964 4000001-4999999 Lawn-Boy C763052 1965 5000001-5999999 Lawn-Boy C763053 1966 600000001-699999999 Lawn-Boy D4303054 1967 700000001-799999999 Lawn-Boy D4303054 1968 800000001-899999999 Lawn-Boy D4303055 1969 900000001-999999999 Lawn-Boy D4313056 1970 000000001-099999999 Lawn-Boy D4323056 1971 100000001-199999999 Lawn-Boy D4323057 1972 200000001-299999999 Lawn-Boy D4323058 1973 300000001-399999999 Lawn-Boy D4313060 1987 F00000001-F99999999 Lawn-Boy F3100 1957 700000001-799999999 Lawn-Boy C203100 1979 900000001-999999999 Piston Powered Products (Ryobi)3130 1979 900000001-999999999 Piston Powered Products (Ryobi)3160 1979 900000001-999999999 Piston Powered Products (Ryobi)3210 1959 900000001-999999999 Lawn-Boy C704230 1983 B00000001-B99999999 Lawn-Boy F4230 1984 C00000001-C99999999 Lawn-Boy F4230 1985 D00000001-D99999999 Lawn-Boy F4250 1983 B00000001-B99999999 Lawn-Boy F4250A 1984 C00000001-C99999999 Lawn-Boy F4260 1985 D00000001-D99999999 Lawn-Boy F4261 1985 D00000001-D99999999 Lawn-Boy F4261 1986 E00000001-E99999999 Lawn-Boy F4262 1986 E00000001-E99999999 Lawn-Boy F4262 1987 F00000001-F99999999 Lawn-Boy F4262 1988 G00000001-G99999999 Lawn-Boy F4263 1988 G00000001-G99999999 Lawn-Boy F4270 1983 B00000001-B99999999 Lawn-Boy F4271 1984 C00000001-C99999999 Lawn-Boy F4271 1985 D00000001-D99999999 Lawn-Boy F4275 1987 F00000001-F99999999 Lawn-Boy F4275 1988 G00000001-G99999999 Lawn-Boy F4275 1989 H00000001-H99999999 Lawn-Boy F4275 1990 J00000001-J99999999 Lawn-Boy F4300 1962 200000001-299999999 Lawn-Boy C184301 1963 300000001-399999999 Lawn-Boy D4004301A 1964 400000001-499999999 Lawn-Boy D4014302 1965 500000001-599999999 Lawn-Boy D4024500 1979 900000001-999999999 Lawn-Boy D4104501 1980 000000001-099999999 Lawn-Boy D4114502 1981 100000001-199999999 Lawn-Boy F3004502 1982 A00000001-A99999999 Lawn-Boy F3004503 1982 A00000001-A99999999 Lawn-Boy F3404505 1983 B00000001-B99999999 Lawn-Boy F3004505A 1984 C00000001-C99999999 Lawn-Boy F301


Page 6 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number4506 1984 C00000001-C99999999 Lawn-Boy F4530 1979 900000001-999999999 Lawn-Boy D4154531 1980 000000001-099999999 Lawn-Boy D4154532 1981 100000001-199999999 Lawn-Boy D4154550 1979 900000001-999999999 Lawn-Boy F1004551 1980 000000001-099999999 Lawn-Boy F1004551 1981 100000001-199999999 Lawn-Boy F1004551 1982 A00000001-A99999999 Lawn-Boy F1004570 1979 900000001-999999999 Lawn-Boy F1004571 1980 000000001-099999999 Lawn-Boy F1004571 1981 100000001-199999999 Lawn-Boy F1004571 1982 A00000001-A99999999 Lawn-Boy F1004571 1983 B00000001-B99999999 Lawn-Boy F1004571 1984 C00000001-C99999999 Lawn-Boy F1004573 1983 B00000001-B99999999 Lawn-Boy F1004600 1984 C00000001-C99999999 Lawn-Boy F4600 1985 D00000001-D99999999 Lawn-Boy F4600 1986 E00000001-E99999999 Lawn-Boy F4602 1988 G00000001-G99999999 Lawn-Boy F4630 1984 C00000001-C99999999 Lawn-Boy F4631 1985 D00000001-D99999999 Lawn-Boy F4631 1986 E00000001-E99999999 Lawn-Boy F4650 1983 B00000001-B99999999 Lawn-Boy F4651 1984 C00000001-C99999999 Lawn-Boy F4651 1985 D00000001-D99999999 Lawn-Boy F4652 1984 C00000001-C99999999 Lawn-Boy F4652 1985 D00000001-D99999999 Lawn-Boy F4656 1986 E00000001-E99999999 Lawn-Boy F4656 1987 F00000001-F99999999 Lawn-Boy F4656 1988 G00000001-G99999999 Lawn-Boy F4656A 1988 G00000001-G99999999 Lawn-Boy F4861 1988 G00000001-G99999999 Lawn-Boy F5000 1956 600000001-699999999 Lawn-Boy C125001 1967 700000001-799999999 Lawn-Boy C185002 1968 800000001-899999999 Lawn-Boy C185003 1969 900000001-999999999 Lawn-Boy C185004 1970 000000001-099999999 Lawn-Boy C185004 1971 100000001-199999999 Lawn-Boy C185006 1982 A00000001-A99999999 Lawn-Boy D4155020 1971 100000001-199999999 Lawn-Boy D4375021 1972 200000001-299999999 Lawn-Boy D4325022 1973 300000001-399999999 Lawn-Boy D4325023 1974 400000001-499999999 Lawn-Boy D4335024 1975 500000001-599999999 Lawn-Boy D4335024 1976 600000001-699999999 Lawn-Boy D4335024 1977 700000001-799999999 Lawn-Boy D4335024 1978 800000001-899999999 Lawn-Boy D433


Page 7 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number5024 1979 900000001-999999999 Lawn-Boy D4335024 1980 000000001-099999999 Lawn-Boy D4335024 1981 100000001-199999999 Lawn-Boy D4335026 1978 800000001-899999999 Lawn-Boy F2005026 1979 900000001-999999999 Lawn-Boy F2005063 1974 400000001-499999999 Lawn-Boy D4335064 1975 500000001-599999999 Lawn-Boy D4335064 1976 600000001-699999999 Lawn-Boy D4335064 1977 700000001-799999999 Lawn-Boy D4335070 1987 F00000001-F99999999 Lawn-Boy F5070 1988 G00000001-G99999999 Lawn-Boy F5070 1989 H00000001-H99999999 Lawn-Boy F5070 1990 J00000001-J99999999 Lawn-Boy F5080 1972 200000001-299999999 Lawn-Boy D4335081 1973 300000001-399999999 Lawn-Boy D4335100 1957 700000001-799999999 Lawn-Boy C125100X 1958 800000001-899999999 Lawn-Boy C125124 1977 700000001-799999999 Lawn-Boy D4095124 1979 900000001-999999999 Lawn-Boy D4095124 1981 100000001-199999999 Lawn-Boy D4095124 1982 A00000001-A99999999 Lawn-Boy D4095125 1981 100000001-199999999 Lawn-Boy D4125126 1982 A00000001-A99999999 Lawn-Boy F3805126 1983 B00000001-B99999999 Lawn-Boy F3805126 1984 C00000001-C99999999 Lawn-Boy F3805126 1985 D00000001-D99999999 Lawn-Boy F3805126 1986 E00000001-E99999999 Lawn-Boy F3805127 1987 F00000001-F99999999 Lawn-Boy F5127 1988 G00000001-G99999999 Lawn-Boy F5200 1958 800000001-899999999 Lawn-Boy C135210 1959 900000001-999999999 Lawn-Boy C145210 1960 000000001-099999999 Lawn-Boy C145210 1961 100000001-199999999 Lawn-Boy C145210A 1961 100000001-199999999 Lawn-Boy C145230 1962 200000001-299999999 Lawn-Boy C175231 1963 300000001-399999999 Lawn-Boy C175232 1964 400000001-499999999 Lawn-Boy D4005233 1965 500000001-599999999 Lawn-Boy D4015234 1966 600000001-699999999 Lawn-Boy D4025235 1967 700000001-799999999 Lawn-Boy D4035236 1968 800000001-899999999 Lawn-Boy D4045237 1968 800000001-899999999 Lawn-Boy D4055238 1969 900000001-999999999 Lawn-Boy D4035239 1970 000000001-099999999 Lawn-Boy D4085239 1971 100000001-199999999 Lawn-Boy D4085239A 1972 200000001-299999999 Lawn-Boy D4085239B 1973 300000001-399999999 Lawn-Boy D408


Page 8 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number5239C 1974 400000001-499999999 Lawn-Boy D4085239D 1975 500000001-599999999 Lawn-Boy D4095239F 1976 600000001-699999999 Lawn-Boy D4095239G 1977 700000001-799999999 Lawn-Boy D4095239G 1978 800000001-899999999 Lawn-Boy D4095239G 1979 900000001-999999999 Lawn-Boy D4095239G 1980 000000001-099999999 Lawn-Boy D4095239G 1981 100000001-199999999 Lawn-Boy D4095240 1972 200000001-299999999 Lawn-Boy D6005241 1973 300000001-399999999 Lawn-Boy D6005242 1974 400000001-499999999 Lawn-Boy D6005243 1975 500000001-599999999 Lawn-Boy D6015244 1976 600000001-699999999 Lawn-Boy D6015245 1977 700000001-799999999 Lawn-Boy D6015245 1978 800000001-899999999 Lawn-Boy D6015247 1978 800000001-899999999 Lawn-Boy F1005247 1979 900000001-999999999 Lawn-Boy F1005247 1980 000000001-099999999 Lawn-Boy F1005247 1981 100000001-199999999 Lawn-Boy F1005247 1982 A00000001-A99999999 Lawn-Boy F1005247 1983 B00000001-B99999999 Lawn-Boy F1015247 1984 C00000001-C99999999 Lawn-Boy F1015247 1985 D00000001-D99999999 Lawn-Boy F1015247 1986 E00000001-E99999999 Lawn-Boy F1015248A 1983 B00000001-B99999999 Lawn-Boy F5248B 1984 C00000001-C99999999 Lawn-Boy F5248B 1985 D00000001-D99999999 Lawn-Boy F5249 1983 B00000001-B99999999 Lawn-Boy F5250 1959 900000001-999999999 Lawn-Boy C605250 1960 000000001-099999999 Lawn-Boy C615250 1961 100000001-199999999 Lawn-Boy C615250A 1962 200000001-299999999 Lawn-Boy C615251 1962 200000001-299999999 Lawn-Boy C615253 1984 C00000001-C99999999 Lawn-Boy F5253 1985 D00000001-D99999999 Lawn-Boy F5253 1986 E00000001-E99999999 Lawn-Boy F5254 1986 E00000001-E99999999 Lawn-Boy F5254 1987 F00000001-F99999999 Lawn-Boy F5254 1988 G00000001-G99999999 Lawn-Boy F5255 1988 G00000001-G99999999 Lawn-Boy F5265 1967 700000001-799999999 Lawn-Boy D4055266 1968 800000001-899999999 Lawn-Boy D4055267 1968 800000001-899999999 Lawn-Boy D4065269 1970 000000001-099999999 Lawn-Boy D4085269 1971 100000001-199999999 Lawn-Boy D4085269 1973 300000001-399999999 Lawn-Boy D4085269A 1972 200000001-299999999 Lawn-Boy D408


Page 9 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number5269B 1973 300000001-399999999 Lawn-Boy D4085269C 1974 400000001-499999999 Lawn-Boy D4085269D 1975 500000001-599999999 Lawn-Boy D4095269D 1976 600000001-699999999 Lawn-Boy D4095269F 1975 500000001-599999999 Lawn-Boy D4095269F 1976 600000001-699999999 Lawn-Boy D4095269G 1977 700000001-799999999 Lawn-Boy D4095269G 1978 800000001-899999999 Lawn-Boy D4095269G 1979 900000001-999999999 Lawn-Boy D4095269G 1980 000000001-099999999 Lawn-Boy D4095269G 1981 100000001-199999999 Lawn-Boy D4095269S 1970 000000001-099999999 Lawn-Boy D4095269S 1971 100000001-199999999 Lawn-Boy D4095270 1972 200000001-299999999 Lawn-Boy D6005271 1973 300000001-399999999 Lawn-Boy D6005272 1974 400000001-499999999 Lawn-Boy D6005273 1975 500000001-599999999 Lawn-Boy D6015273 1976 600000001-699999999 Lawn-Boy D6015274 1976 600000001-699999999 Lawn-Boy D6015275 1977 700000001-799999999 Lawn-Boy D6015275 1978 800000001-899999999 Lawn-Boy D6015277 1978 800000001-899999999 Lawn-Boy F1005277 1979 900000001-999999999 Lawn-Boy F1005277 1980 000000001-099999999 Lawn-Boy F1005277 1981 100000001-199999999 Lawn-Boy F1005277 1982 A00000001-A99999999 Lawn-Boy F1005277 1983 B00000001-B99999999 Lawn-Boy F1005277 1984 C00000001-C99999999 Lawn-Boy F1005277 1985 D00000001-D99999999 Lawn-Boy F1005278 1988 G00000001-G99999999 Lawn-Boy F10060-1618-2 1982 A00000001-A99999999 Lawn-Boy F20160-1618-2 1983 B00000001-B99999999 Lawn-Boy F60-1618-2 1984 C00000001-C99999999 Lawn-Boy F60-1618-2 1985 D00000001-D99999999 Lawn-Boy F6100 1957 400000001-799999999 Lawn-Boy C406116 1969 900000001-999999999 Lawn-Boy C416117 1969 900000001-999999999 Lawn-Boy C416120 1986 E00000001-E99999999 Lawn-Boy C416200 1958 800000001-899999999 Lawn-Boy C416210 1959 900000001-999999999 Lawn-Boy C416211 1984 C00000001-C99999999 Lawn-Boy F6211 1985 D00000001-D99999999 Lawn-Boy F6212 1984 C00000001-C99999999 Lawn-Boy F6212 1985 D00000001-D99999999 Lawn-Boy F6221 1984 C00000001-C99999999 Lawn-Boy F6221 1985 D00000001-D99999999 Lawn-Boy F6222 1987 F00000001-F99999999 Lawn-Boy F


Page 10 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number6222 1988 G00000001-G99999999 Lawn-Boy F6222 1989 H00000001-H99999999 Lawn-Boy F6222 1990 J00000001-J99999999 Lawn-Boy F6230 1986 E00000001-E99999999 Lawn-Boy F6250 1964 400000001-499999999 Lawn-Boy C196251 1965 500000001-599999999 Lawn-Boy C196251 1966 600000001-699999999 Lawn-Boy C196252 1966 600000001-699999999 Lawn-Boy C196252 1967 700000001-799999999 Lawn-Boy C196252 1968 800000001-899999999 Lawn-Boy C196252 1969 900000001-999999999 Lawn-Boy C196252 1970 000000001-099999999 Lawn-Boy C196252 1971 100000001-199999999 Lawn-Boy C196253 1972 200000001-299999999 Lawn-Boy D4766254 1973 300000001-399999999 Lawn-Boy D4766254 1974 400000001-499999999 Lawn-Boy D4766255 1975 500000001-599999999 Lawn-Boy D4766255 1976 600000001-699999999 Lawn-Boy D4766255 1977 700000001-799999999 Lawn-Boy D4766255 1978 800000001-899999999 Lawn-Boy D4766257 1978 800000001-899999999 Lawn-Boy F2006257 1979 900000001-999999999 Lawn-Boy F2006258 1978 800000001-899999999 Lawn-Boy F2006258 1979 900000001-999999999 Lawn-Boy F2006259 1980 000000001-099999999 Lawn-Boy F2016259 1981 100000001-199999999 Lawn-Boy F2016259 1982 A00000001-A99999999 Lawn-Boy F2016259 1983 B00000001-B99999999 Lawn-Boy F2016259 1984 C00000001-C99999999 Lawn-Boy F2016259 1985 D00000001-D99999999 Lawn-Boy F2016259 1986 E00000001-E99999999 Lawn-Boy F2016260 1981 100000001-199999999 Lawn-Boy F2016261 1983 B00000001-B99999999 Lawn-Boy F6262 1984 C00000001-C99999999 Lawn-Boy F6275 1969 900000001-999999999 Lawn-Boy D4756275 1970 000000001-099999999 Lawn-Boy D4766275 1971 100000001-199999999 Lawn-Boy D4766275 1972 200000001-299999999 Lawn-Boy D4766276 1973 300000001-399999999 Lawn-Boy D4766276 1974 400000001-499999999 Lawn-Boy D4766277 1975 500000001-599999999 Lawn-Boy D4766277 1976 600000001-699999999 Lawn-Boy D4766277 1977 700000001-799999999 Lawn-Boy D4766279 1978 800000001-899999999 Lawn-Boy F2006279 1979 900000001-999999999 Lawn-Boy F2006280 1980 000000001-099999999 Lawn-Boy F2016280 1981 100000001-199999999 Lawn-Boy F201


Page 11 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number6280 1982 A00000001-A99999999 Lawn-Boy F2016280 1983 300000001-399999999 Lawn-Boy F2016280 1984 C00000001-C99999999 Lawn-Boy F2016280 1985 D00000001-D99999999 Lawn-Boy F2016286 1983 B00000001-B99999999 Lawn-Boy F6290 1979 900000001-999999999 Lawn-Boy F2006290 1980 000000001-099999999 Lawn-Boy F2006290 1981 100000001-199999999 Lawn-Boy F2006291 1980 000000001-099999999 Lawn-Boy F2016291 1981 100000001-199999999 Lawn-Boy F2016300 1980 000000001-099999999 Lawn-Boy F2016300 1981 100000001-199999999 Lawn-Boy F2016300 1982 A00000001-A99999999 Lawn-Boy F2016301 1983 B00000001-B99999999 Lawn-Boy F2016302 1984 C00000001-C99999999 Lawn-Boy F2016302 1985 D00000001-D99999999 Lawn-Boy F2016350 1980 000000001-099999999 Lawn-Boy F2016420 1983 B00000001-B99999999 Lawn-Boy F6421 1984 C00000001-C99999999 Lawn-Boy F6421 1985 D00000001-D99999999 Lawn-Boy F6430 1986 E00000001-E99999999 Lawn-Boy F6431 1987 F00000001-F99999999 Lawn-Boy F6431 1988 G00000001-G99999999 Lawn-Boy F6461 1986 E00000001-E99999999 Lawn-Boy F6461 1987 F00000001-F99999999 Lawn-Boy F6461 1988 G00000001-G99999999 Lawn-Boy F680521 1992 L00000001-L99999999 Lawn-Boy F680526 1992 L00000001-L99999999 Lawn-Boy F680527 1992 L00000001-L99999999 Lawn-Boy F680528 1992 L00000001-L99999999 Lawn-Boy F680529 1992 L00000001-L99999999 Lawn-Boy F680530 1992 L00000001-L99999999 Lawn-Boy F680532 1991 K00000001-K99999999 Briggs & Stratton 126702-3192680532 1992 L00000001-L99999999 Briggs & Stratton 126702-3192680539 1992 L00000001-L99999999 Briggs & Stratton 126702-3192680540 1992 L00000001-L99999999 Lawn-Boy F680541 1992 L00000001-L99999999 Lawn-Boy F680542 1992 L00000001-L99999999 Lawn-Boy F680543 1992 L00000001-L99999999 Lawn-Boy F680544 1992 L00000001-L99999999 Lawn-Boy F680545 1992 L00000001-L99999999 Lawn-Boy F680546 1992 L00000001-L99999999 Lawn-Boy F680547 1991 K00000001-K99999999 Briggs & Stratton 126702-3192680547 1992 L00000001-L99999999 Briggs & Stratton 126702-3192680548 1991 K00000001-K99999999 Briggs & Stratton 126702-3192680548 1992 L00000001-L99999999 Briggs & Stratton 126702-3192680550 1992 L00000001-L99999999 Lawn-Boy F


Page 12 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number680551 1992 L00000001-L99999999 Lawn-Boy F680552 1992 L00000001-L99999999 Lawn-Boy F680553 1992 L00000001-L99999999 Lawn-Boy F680554 1992 L00000001-L99999999 Lawn-Boy F680555 1992 L00000001-L99999999 Lawn-Boy F680558 1992 L00000001-L99999999 Lawn-Boy F680559 1992 L00000001-L99999999 Lawn-Boy F680560 1992 L00000001-L99999999 Lawn-Boy F680561 1992 L00000001-L99999999 Lawn-Boy F680565 1992 L00000001-L99999999 Lawn-Boy F680566 1992 L00000001-L99999999 Lawn-Boy F7000 1956 600000001-699999999 Lawn-Boy C187001 1966 600000001-699999999 Lawn-Boy C187001 1967 700000001-799999999 Lawn-Boy C187002 1968 800000001-899999999 Lawn-Boy C187003 1969 900000001-999999999 Lawn-Boy C187004 1970 000000001-099999999 Lawn-Boy C187004 1971 100000001-199999999 Lawn-Boy C187010 1968 800000001-899999999 Lawn-Boy C187010 1969 900000001-999999999 Lawn-Boy C187011 1969 900000001-999999999 Lawn-Boy C187012 1970 000000001-099999999 Lawn-Boy C187012 1971 100000001-199999999 Lawn-Boy C187020 1970 000000001-099999999 Lawn-Boy C207020 1971 100000001-199999999 Lawn-Boy C207021 1972 200000001-299999999 Lawn-Boy D4337022 1973 300000001-399999999 Lawn-Boy D4337023 1974 400000001-499999999 Lawn-Boy D4337024 1975 500000001-599999999 Lawn-Boy D4337024 1976 600000001-699999999 Lawn-Boy D4337024 1977 700000001-799999999 Lawn-Boy D4337025 1978 800000001-899999999 Lawn-Boy D4537025 1979 900000001-999999999 Lawn-Boy F2007035 1986 E00000001-E99999999 Lawn-Boy F7050 1959 900000001-999999999 Lawn-Boy C707050 1982 A00000001-A99999999 Lawn-Boy F3207050 1983 B00000001-B99999999 Lawn-Boy F3207050 1984 C00000001-C99999999 Lawn-Boy F3207050 1985 D00000001-D99999999 Lawn-Boy F3207050 1986 E00000001-E99999999 Lawn-Boy F3207064 1970 000000001-099999999 Lawn-Boy C18B7064 1971 100000001-199999999 Lawn-Boy C18B7070 1980 000000001-099999999 Lawn-Boy F1007071 1981 100000001-199999999 Lawn-Boy F1017071 1982 A00000001-A99999999 Lawn-Boy F1017072 1984 C00000001-C99999999 Lawn-Boy F7072 1985 D00000001-D99999999 Lawn-Boy F


Page 13 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number7072A 1986 E00000001-E99999999 Lawn-Boy F7072JP 1984 C00000001-C99999999 Lawn-Boy F7073 1986 E00000001-E99999999 Lawn-Boy F7073 1987 F00000001-F99999999 Lawn-Boy F7073 1988 G00000001-G99999999 Lawn-Boy F7073B 1987 F00000001-F99999999 Lawn-Boy F7074 1988 G00000001-G99999999 Lawn-Boy F7080 1970 000000001-099999999 Lawn-Boy D4317080 1971 100000001-199999999 Lawn-Boy D4317081 1972 200000001-299999999 Lawn-Boy D4337082 1973 300000001-399999999 Lawn-Boy D4337083 1974 400000001-499999999 Lawn-Boy D4337084 1975 500000001-599999999 Lawn-Boy D4337084 1976 600000001-699999999 Lawn-Boy D4337084 1977 700000001-799999999 Lawn-Boy D4337084 1978 800000001-899999999 Lawn-Boy D4337086 1978 800000001-899999999 Lawn-Boy F2007086 1979 900000001-999999999 Lawn-Boy F2007100 1957 400000001-499999999 Lawn-Boy C127100X 1958 800000001-899999999 Lawn-Boy C127150 1982 A00000001-A99999999 Lawn-Boy C127150 1983 B00000001-B99999999 Lawn-Boy F3207200 1958 800000001-899999999 Lawn-Boy C137210 1959 900000001-999999999 Lawn-Boy C147210 1960 000000001-099999999 Lawn-Boy C147210 1961 100000001-199999999 Lawn-Boy C147210A 1961 100000001-199999999 Lawn-Boy C147214 1964 400000001-499999999 Lawn-Boy D4017215 1965 500000001-599999999 Lawn-Boy D4027216 1966 600000001-699999999 Lawn-Boy D4037217 1967 700000001-799999999 Lawn-Boy D4047218 1968 800000001-899999999 Lawn-Boy D4057219 1968 800000001-899999999 Lawn-Boy D4067220 1969 900000001-999999999 Lawn-Boy D4077221 1970 000000001-099999999 Lawn-Boy D4087221 1971 100000001-199999999 Lawn-Boy D4087221 1972 200000001-299999999 Lawn-Boy D4087221A 1972 200000001-299999999 Lawn-Boy D4087221B 1973 300000001-399999999 Lawn-Boy D4087221C 1974 400000001-499999999 Lawn-Boy D4087221D 1975 500000001-599999999 Lawn-Boy D4097221F 1976 600000001-699999999 Lawn-Boy D4097221G 1977 700000001-799999999 Lawn-Boy D4097221G 1978 800000001-899999999 Lawn-Boy D4097221G 1979 900000001-999999999 Lawn-Boy D4097221G 1980 000000001-099999999 Lawn-Boy D4097221G 1981 100000001-199999999 Lawn-Boy D409


Page 14 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number7222 1972 200000001-299999999 Lawn-Boy D6007223 1973 300000001-399999999 Lawn-Boy D6007224 1974 400000001-499999999 Lawn-Boy D6007225 1975 500000001-599999999 Lawn-Boy D6017226 1976 600000001-699999999 Lawn-Boy D6017227 1977 700000001-799999999 Lawn-Boy D6017227 1978 800000001-899999999 Lawn-Boy D6017229 1978 800000001-899999999 Lawn-Boy F1007229 1979 900000001-999999999 Lawn-Boy F1007229 1980 000000001-099999999 Lawn-Boy F1007229 1981 100000001-199999999 Lawn-Boy F1007229 1982 A00000001-A99999999 Lawn-Boy F1007229 1983 B00000001-B99999999 Lawn-Boy F1007229 1984 C00000001-C99999999 Lawn-Boy F1007229 1985 D00000001-D99999999 Lawn-Boy F1007229G 1980 000000001-099999999 Lawn-Boy F1007231 1983 B00000001-B99999999 Lawn-Boy F1007232 1984 C00000001-C99999999 Lawn-Boy F1007240 1988 G00000001-G99999999 Lawn-Boy F1007250 1960 000000001-099999999 Lawn-Boy C157250 1961 100000001-199999999 Lawn-Boy C157251 1962 200000001-299999999 Lawn-Boy C187252 1964 400000001-499999999 Lawn-Boy D4007253 1964 400000001-499999999 Lawn-Boy C187254 1965 500000001-599999999 Lawn-Boy D4007254WB 1965 500000001-599999999 Lawn-Boy D4017255 1966 600000001-699999999 Lawn-Boy D4037256 1967 700000001-799999999 Lawn-Boy D4047257 1968 800000001-899999999 Lawn-Boy D4057258 1968 800000001-899999999 Lawn-Boy D4067258E 1968 800000001-899999999 Lawn-Boy D406E7258E 1969 900000001-999999999 Lawn-Boy D406E7259 1969 900000001-999999999 Lawn-Boy D4077259E 1969 900000001-999999999 Lawn-Boy D407E7260 1970 000000001-099999999 Lawn-Boy D4087260 1971 100000001-199999999 Lawn-Boy D4087260A 1972 200000001-299999999 Lawn-Boy D4087260B 1973 300000001-399999999 Lawn-Boy D4087260C 1974 400000001-499999999 Lawn-Boy D4087260D 1975 500000001-599999999 Lawn-Boy D4097260D 1976 600000001-699999999 Lawn-Boy D4097260E 1970 000000001-099999999 Lawn-Boy D408E7260E 1971 100000001-199999999 Lawn-Boy D408E7260F 1976 600000001-699999999 Lawn-Boy D4097260G 1977 700000001-799999999 Lawn-Boy D4097260G 1978 800000001-899999999 Lawn-Boy D4097260G 1979 900000001-999999999 Lawn-Boy D409


Page 15 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number7260G 1980 000000001-099999999 Lawn-Boy D4097260G 1981 100000001-199999999 Lawn-Boy D4097260S 1970 000000001-099999999 Lawn-Boy D4097260S 1971 100000001-199999999 Lawn-Boy D4097261 1972 200000001-299999999 Lawn-Boy D6007261E 1972 200000001-299999999 Lawn-Boy D6007262 1973 300000001-399999999 Lawn-Boy D6007262E 1973 300000001-399999999 Lawn-Boy D600E7263 1974 400000001-499999999 Lawn-Boy D6007263E 1974 400000001-499999999 Lawn-Boy D601E7264 1975 500000001-599999999 Lawn-Boy D6017264 1976 600000001-699999999 Lawn-Boy D6017265 1976 600000001-699999999 Lawn-Boy D6017266 1977 700000001-799999999 Lawn-Boy D6017266 1978 800000001-899999999 Lawn-Boy D6017268 1978 800000001-899999999 Lawn-Boy F1007268 1979 900000001-999999999 Lawn-Boy F1007268 1980 000000001-099999999 Lawn-Boy F1007268 1981 100000001-199999999 Lawn-Boy F1007268 1982 A00000001-A99999999 Lawn-Boy F1007268A 1986 E00000001-E99999999 Lawn-Boy F1007270 1983 B00000001-B99999999 Lawn-Boy F1007270AE 1983 B00000001-B99999999 Lawn-Boy F7271 1984 C00000001-C99999999 Lawn-Boy F7271AE 1984 C00000001-C99999999 Lawn-Boy F7350 1985 D00000001-D99999999 Lawn-Boy F7351 1986 E00000001-E99999999 Lawn-Boy F7351 1987 F00000001-F99999999 Lawn-Boy F7351 1988 G00000001-G99999999 Lawn-Boy F7352 1988 G00000001-G99999999 Lawn-Boy F8001 1966 600000001-699999999 Lawn-Boy C438001 1967 700000001-799999999 Lawn-Boy C438002 1967 700000001-799999999 Lawn-Boy C448003 1968 800000001-899999999 Lawn-Boy C458004 1969 900000001-999999999 Lawn-Boy C458005 1970 000000001-099999999 Lawn-Boy C468005 1971 100000001-199999999 Lawn-Boy C468020 1970 000000001-099999999 Lawn-Boy C468020 1971 100000001-199999999 Lawn-Boy D4208021 1972 200000001-299999999 Lawn-Boy D4208025 1984 C00000001-C99999999 Lawn-Boy F8025 1985 D00000001-D99999999 Lawn-Boy F8035 1986 E00000001-E99999999 Lawn-Boy F8035AE 1986 E00000001-E99999999 Lawn-Boy F8070 1980 000000001-099999999 Lawn-Boy F1408071 1980 000000001-099999999 Lawn-Boy F1418071 1981 100000001-199999999 Lawn-Boy F141


Page 16 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number8071 1982 A00000001-A99999999 Lawn-Boy F1418072 1984 C00000001-C99999999 Lawn-Boy F8072 1985 D00000001-D99999999 Lawn-Boy F8073 1986 E00000001-E99999999 Lawn-Boy F8073 1987 F00000001-F99999999 Lawn-Boy F8073 1988 G00000001-G99999999 Lawn-Boy F8073AE 1988 G00000001-G99999999 Lawn-Boy F8074 1988 G00000001-G99999999 Lawn-Boy F8100 1957 700000001-799999999 Lawn-Boy C408110 1986 E00000001-E99999999 Lawn-Boy F8125 1984 C00000001-C99999999 Lawn-Boy F8125 1985 D00000001-D99999999 Lawn-Boy F8125 1986 E00000001-E99999999 Lawn-Boy F8127AE 1988 G00000001-G99999999 Lawn-Boy F8155 1986 E00000001-E99999999 Lawn-Boy F8156 1987 F00000001-F99999999 Lawn-Boy F8157 1986 E00000001-E99999999 Lawn-Boy F8157 1987 F00000001-F99999999 Lawn-Boy F8157 1988 G00000001-G99999999 Lawn-Boy F8157A 1987 F00000001-F99999999 Lawn-Boy F8157A 1988 G00000001-G99999999 Lawn-Boy F8157A1 1989 H00000001-H99999999 Lawn-Boy F8157A1 1990 J00000001-J99999999 Lawn-Boy F8200 1958 800000001-899999999 Lawn-Boy C418210 1959 900000001-999999999 Lawn-Boy C418210 1960 000000001-099999999 Lawn-Boy C418210 1961 100000001-199999999 Lawn-Boy C418210A 1961 100000001-199999999 Lawn-Boy C418220 1962 200000001-299999999 Lawn-Boy C438221 1963 300000001-399999999 Lawn-Boy D4408222 1964 400000001-499999999 Lawn-Boy D4418223 1965 500000001-599999999 Lawn-Boy D4428224 1966 600000001-699999999 Lawn-Boy D4438225 1967 700000001-799999999 Lawn-Boy D4448226 1967 700000001-799999999 Lawn-Boy D4458226 1968 800000001-899999999 Lawn-Boy D4458227 1968 800000001-899999999 Lawn-Boy D4468227E 1968 800000001-899999999 Lawn-Boy D446E8228 1969 900000001-999999999 Lawn-Boy D4478228E 1969 900000001-999999999 Lawn-Boy D477E8229 1970 000000001-099999999 Lawn-Boy D4488229 1971 100000001-199999999 Lawn-Boy D4488229A 1970 000000001-099999999 Lawn-Boy D4488229A 1971 100000001-199999999 Lawn-Boy D4488229A 1972 200000001-299999999 Lawn-Boy D4488229B 1972 200000001-299999999 Lawn-Boy D4488229C 1973 300000001-399999999 Lawn-Boy D448


Page 17 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number8229D 1974 400000001-499999999 Lawn-Boy D4498229DV 1974 400000001-499999999 Lawn-Boy D4498229E 1970 000000001-099999999 Lawn-Boy D449E8229E 1971 100000001-199999999 Lawn-Boy D449E8229EA 1972 200000001-299999999 Lawn-Boy D449E8229F 1975 500000001-599999999 Lawn-Boy D4498229F 1976 600000001-699999999 Lawn-Boy D4498229H 1977 700000001-799999999 Lawn-Boy D4498229H 1978 800000001-899999999 Lawn-Boy D4498229S 1970 000000001-099999999 Lawn-Boy D4488229S 1971 100000001-199999999 Lawn-Boy D4488230 1972 200000001-299999999 Lawn-Boy D6408230E 1972 200000001-299999999 Lawn-Boy D640E8231 1973 300000001-399999999 Lawn-Boy D6408231E 1973 300000001-399999999 Lawn-Boy D640E8232 1974 400000001-499999999 Lawn-Boy D6408232E 1974 400000001-499999999 Lawn-Boy D640E8233 1975 500000001-599999999 Lawn-Boy D6418233 1976 600000001-699999999 Lawn-Boy D6418233AE 1975 500000001-599999999 Lawn-Boy D641E8233E 1976 600000001-699999999 Lawn-Boy D641E8234 1976 600000001-699999999 Lawn-Boy D6408234AE 1976 600000001-699999999 Lawn-Boy D641E8235 1977 700000001-799999999 Lawn-Boy D6418235 1978 800000001-899999999 Lawn-Boy D6418235AE 1977 700000001-799999999 Lawn-Boy D641AE8235AE 1978 800000001-899999999 Lawn-Boy D641AE8237 1978 800000001-899999999 Lawn-Boy F1408237 1979 900000001-999999999 Lawn-Boy F1408237 1980 000000001-099999999 Lawn-Boy F1408237 1981 100000001-199999999 Lawn-Boy F1408237 1982 A00000001-A99999999 Lawn-Boy F1408237 1983 B00000001-B99999999 Lawn-Boy F1408237AE 1978 800000001-899999999 Lawn-Boy F140AE8238AE 1979 900000001-999999999 Lawn-Boy F140AE8238AE 1980 000000001-099999999 Lawn-Boy F140AE8238AE 1981 100000001-199999999 Lawn-Boy F140AE8238AE 1982 A00000001-A99999999 Lawn-Boy F140AE8239AE 1984 C00000001-C99999999 Lawn-Boy F140AE8240 1983 B00000001-B99999999 Lawn-Boy F8240AE 1983 B00000001-B99999999 Lawn-Boy F8241 1984 C00000001-C99999999 Lawn-Boy F8241 1985 D00000001-D99999999 Lawn-Boy F8241 1986 E00000001-E99999999 Lawn-Boy F8241AE 1984 C00000001-C99999999 Lawn-Boy F8241AE 1985 D00000001-D99999999 Lawn-Boy F8243 1986 E00000001-E99999999 Lawn-Boy F


Page 18 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number8243 1987 F00000001-F99999999 Lawn-Boy F8243 1988 G00000001-G99999999 Lawn-Boy F8243AE 1986 E00000001-E99999999 Lawn-Boy F8243AE 1987 F00000001-F99999999 Lawn-Boy F8243AE1 1988 G00000001-G99999999 Lawn-Boy F8243B 1988 G00000001-G99999999 Lawn-Boy F8244 1988 G00000001-G99999999 Lawn-Boy F8250 1973 300000001-399999999 Lawn-Boy D4808250X 1973 300000001-399999999 Lawn-Boy D4808251 1974 400000001-499999999 Lawn-Boy D4808252 1975 500000001-599999999 Lawn-Boy D4818252 1976 600000001-699999999 Lawn-Boy D4818253 1976 600000001-699999999 Lawn-Boy D4818255 1977 700000001-799999999 Lawn-Boy D4818255 1978 800000001-899999999 Lawn-Boy D4818255 1979 900000001-999999999 Lawn-Boy D4818256 1979 900000001-999999999 Lawn-Boy D4818256 1980 000000001-099999999 Lawn-Boy D4818256 1981 100000001-199999999 Lawn-Boy D4818270 1978 800000001-899999999 Lawn-Boy F1408270 1979 900000001-999999999 Lawn-Boy F1408270 1980 000000001-099999999 Lawn-Boy F1408270 1981 100000001-199999999 Lawn-Boy F1408270 1982 A00000001-A99999999 Lawn-Boy F1418270 1983 B00000001-B99999999 Lawn-Boy F1418270 1984 C00000001-C99999999 Lawn-Boy F1418270A 1985 D00000001-D99999999 Lawn-Boy F1418270A 1986 E00000001-E99999999 Lawn-Boy F1418270AE 1978 800000001-899999999 Lawn-Boy F140AE8271AE 1978 800000001-899999999 Lawn-Boy F140AE8271AE 1979 900000001-999999999 Lawn-Boy F140AE8271AE 1980 000000001-099999999 Lawn-Boy F140AE8271AE 1981 100000001-199999999 Lawn-Boy F140AE8271AE 1982 A00000001-A99999999 Lawn-Boy F142AE8272 1983 B00000001-B99999999 Lawn-Boy F8272AE 1983 B00000001-B99999999 Lawn-Boy F8273 1984 C00000001-C99999999 Lawn-Boy F8273 1985 D00000001-D99999999 Lawn-Boy F8273AE 1984 C00000001-C99999999 Lawn-Boy F8273AE 1985 D00000001-D99999999 Lawn-Boy F8290 1983 B00000001-B99999999 Lawn-Boy F8291 1984 C00000001-C99999999 Lawn-Boy F8291 1985 D00000001-D99999999 Lawn-Boy F8310 1978 800000001-899999999 Lawn-Boy F8310 1979 900000001-999999999 Lawn-Boy F2408350 1978 800000001-899999999 Lawn-Boy F2408350 1979 900000001-999999999 Lawn-Boy F240


Page 19 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number8400 1980 000000001-099999999 Lawn-Boy F2418401 1980 000000001-099999999 Lawn-Boy F2418401 1981 100000001-199999999 Lawn-Boy F2418401 1982 A00000001-A99999999 Lawn-Boy F2418401 1983 B00000001-B99999999 Lawn-Boy F2418401 1984 C00000001-C99999999 Lawn-Boy F2418401B 1985 D00000001-D99999999 Lawn-Boy F2418402 1983 B00000001-B99999999 Lawn-Boy F2418403 1984 C00000001-C99999999 Lawn-Boy F2418403 1985 D00000001-D99999999 Lawn-Boy F2418426 1983 B00000001-B99999999 Lawn-Boy F8427 1984 C00000001-C99999999 Lawn-Boy F8427 1985 D00000001-D99999999 Lawn-Boy F8430 1986 E00000001-E99999999 Lawn-Boy F8431 1986 E00000001-E99999999 Lawn-Boy F8431 1987 F00000001-F99999999 Lawn-Boy F8431 1988 G00000001-G99999999 Lawn-Boy F8440 1987 F00000001-F99999999 Lawn-Boy F8440 1988 G00000001-G99999999 Lawn-Boy F8440 1989 H00000001-H99999999 Lawn-Boy F8440 1990 J00000001-J99999999 Lawn-Boy F8440AE 1987 F00000001-F99999999 Lawn-Boy F8440AE 1988 G00000001-G99999999 Lawn-Boy F8440AE 1989 H00000001-H99999999 Lawn-Boy F8440AE 1990 J00000001-J99999999 Lawn-Boy F8453 1985 D00000001-D99999999 Lawn-Boy F8455 1987 F00000001-F99999999 Lawn-Boy F8461 1986 E00000001-E99999999 Lawn-Boy F8461 1987 F00000001-F99999999 Lawn-Boy F8461 1988 G00000001-G99999999 Lawn-Boy F8471 1987 F00000001-F99999999 Lawn-Boy F8480 1986 E00000001-E99999999 Lawn-Boy F8481 1986 E00000001-E99999999 Lawn-Boy F8481 1987 F00000001-F99999999 Lawn-Boy F8481 1988 G00000001-G99999999 Lawn-Boy F8481AE 1986 E00000001-E99999999 Lawn-Boy F8481AE 1987 F00000001-F99999999 Lawn-Boy F8481AE 1988 G00000001-G99999999 Lawn-Boy F8600 1979 900000001-999999999 Lawn-Boy D4108601 1980 000000001-099999999 Lawn-Boy D4118602 1981 100000001-199999999 Lawn-Boy F3408602 1982 A00000001-A99999999 Lawn-Boy F3408603 1982 A00000001-A99999999 Lawn-Boy F3408604 1983 B00000001-B99999999 Lawn-Boy F8604A 1984 C00000001-C99999999 Lawn-Boy F8604A 1985 D00000001-D99999999 Lawn-Boy F8605 1983 B00000001-B99999999 Lawn-Boy F340


Page 20 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number8605A 1984 C00000001-C99999999 Lawn-Boy F3408650 1979 900000001-999999999 Lawn-Boy F3408651 1980 000000001-099999999 Lawn-Boy F1408651 1981 100000001-199999999 Lawn-Boy F1408651 1982 A00000001-A99999999 Lawn-Boy F1408670 1979 900000001-999999999 Lawn-Boy F1408671 1980 000000001-099999999 Lawn-Boy F1418671 1981 100000001-199999999 Lawn-Boy F1418671 1982 A00000001-A99999999 Lawn-Boy F1418671AE 1980 000000001-099999999 Lawn-Boy F1418671AE 1981 100000001-199999999 Lawn-Boy F142AE8671AE 1982 A00000001-A99999999 Lawn-Boy F142AE8673 1983 B00000001-B99999999 Lawn-Boy F8673AE 1983 B00000001-B99999999 Lawn-Boy F8674 1984 C00000001-C99999999 Lawn-Boy F8861 1988 G00000001-G99999999 Lawn-Boy F9200 1958 800000001-899999999 Lawn-Boy C509210 1959 900000001-999999999 Lawn-Boy C509210 1960 000000001-099999999 Lawn-Boy C509210 1961 100000001-199999999 Lawn-Boy C509211 1962 200000001-299999999 Lawn-Boy D4509212 1963 300000001-399999999 Lawn-Boy D4509212A 1964 400000001-499999999 Lawn-Boy D4519213 1965 500000001-599999999 Lawn-Boy D4529266 1974 400000001-499999999 Briggs & Stratton 1309029266 1975 500000001-599999999 Briggs & Stratton 1309029266 1976 600000001-699999999 Briggs & Stratton 1309029300 1967 700000001-799999999 Briggs & Stratton 146702-06529300 1968 800000001-899999999 Briggs & Stratton 146702-06529301 1969 900000001-999999999 Briggs & Stratton 146702-06529302 1970 000000001-099999999 Briggs & Stratton 146702-06529302 1971 100000001-199999999 Briggs & Stratton 146702-06529302E 1969 900000001-999999999 Tecumseh V70-1250469302E 1970 000000001-099999999 Tecumseh V70-1250469302E 1971 100000001-199999999 Tecumseh V70-1250469303 1970 000000001-099999999 Briggs & Stratton 270702-06629303 1971 100000001-199999999 Briggs & Stratton 270702-06629303E 1970 000000001-099999999 Tecumseh V70-1250469303E 1971 100000001-199999999 Tecumseh V70-1250469328 1972 200000001-299999999 Briggs & Stratton 1907029328E 1972 200000001-299999999 Briggs & Stratton 1907079328ES 1972 200000001-299999999 Briggs & Stratton 1917079329 1974 400000001-499999999 Briggs & Stratton 1907029329 1975 500000001-599999999 Briggs & Stratton 1907029329 1976 600000001-699999999 Briggs & Stratton 1907029329E 1974 400000001-499999999 Briggs & Stratton 1907079329E 1975 500000001-599999999 Briggs & Stratton 190707


Page 21 of 23

Model Year Serial Range Engine Manuafacturer Engine Model Number9329E 1976 600000001-699999999 Briggs & Stratton 1907079329ES 1973 300000001-399999999 Briggs & Stratton 1917079329ES 1974 400000001-499999999 Briggs & Stratton 1917079329ES 1975 500000001-599999999 Briggs & Stratton 1917079329ES 1976 600000001-699999999 Briggs & Stratton 1917079368 1972 200000001-299999999 Briggs & Stratton 1907029368E 1972 200000001-299999999 Briggs & Stratton 1907079368ES 1972 200000001-299999999 Briggs & Stratton 1917079369 1974 400000001-499999999 Briggs & Stratton 1907029369 1975 500000001-599999999 Briggs & Stratton 1907029369 1976 600000001-699999999 Briggs & Stratton 1907029369E 1974 400000001-499999999 Briggs & Stratton 1907079369E 1975 500000001-599999999 Briggs & Stratton 1907079369E 1976 600000001-699999999 Briggs & Stratton 1907079369ES 1974 400000001-499999999 Briggs & Stratton 1917079369ES 1975 500000001-599999999 Briggs & Stratton 1917079369ES 1976 600000001-699999999 Briggs & Stratton 1917079500 1971 100000001-199999999 Briggs & Stratton 1309029501 1972 200000001-299999999 Briggs & Stratton 1309029600 1969 900000001-999999999 Briggs & Stratton 146702-06529601 1970 000000001-099999999 Briggs & Stratton 146702-06529601 1971 100000001-199999999 Briggs & Stratton 146702-0652C20CPR 1989 H00000001-H99999999 Lawn-Boy FC20CSR 1989 H00000001-H99999999 Lawn-Boy FC21CPN 1989 H00000001-H99999999 Lawn-Boy FC21CPN 1990 J00000001-J99999999 Lawn-Boy FC21CPNA 1990 J00000001-J99999999 Lawn-Boy FC21CSN 1989 H00000001-H99999999 Lawn-Boy FC21ZPN 1991 K00000001-K99999999 Lawn-Boy FC21ZSN 1991 K00000001-K99999999 Lawn-Boy FCS19ZPN 1990 J00000001-J99999999 Lawn-Boy FCS19ZPNA 1991 K00000001-K99999999 Lawn-Boy FEL20ZPR 1991 K00000001-K99999999 Lawn-Boy FES19ZPN 1991 K00000001-K99999999 Lawn-Boy FES20ESR 1991 K00000001-K99999999 Lawn-Boy FES20ZSR 1991 K00000001-K99999999 Lawn-Boy FET-1 1960 000000001-099999999 Lawn-Boy C71H21CPN 1989 H00000001-H99999999 Lawn-Boy FL20ZPN 1989 H00000001-H99999999 Lawn-Boy FL20ZPR 1989 H00000001-H99999999 Lawn-Boy FL20ZPRA 1989 H00000001-H99999999 Lawn-Boy FL20ZPRB 1990 J00000001-J99999999 Lawn-Boy FL21ZPN 1989 H00000001-H99999999 Lawn-Boy FL21ZPNA 1989 H00000001-H99999999 Lawn-Boy FL21ZPNB 1990 J00000001-J99999999 Lawn-Boy FL21ZPNC 1991 K00000001-K99999999 Lawn-Boy FL21ZSN 1989 H00000001-H99999999 Lawn-Boy F


Page 22 of 23

Model Year Serial Range Engine Manuafacturer Engine Model NumberL21ZSNA 1989 H00000001-H99999999 Lawn-Boy FL21ZSNB 1990 J00000001-J99999999 Lawn-Boy FL21ZSNC 1991 K00000001-K99999999 Lawn-Boy FLPT 1960 000000001-099999999 Clinton B1290LPT 1961 100000001-199999999 Clinton B1290LVT-1 1960 000000001-099999999 Lawn-Boy C80LVT-1 1961 100000001-199999999 Lawn-Boy C80M70BC 1961 100000001-199999999 Briggs & Stratton 706018R7070 1980 000000001-099999999 Lawn-Boy F100R7070 1981 100000001-199999999 Lawn-Boy F100R7268 1978 800000001-899999999 Lawn-Boy F100R7268 1979 900000001-999999999 Lawn-Boy F100R7268 1980 000000001-099999999 Lawn-Boy F100R7268 1981 100000001-199999999 Lawn-Boy F100R7268 1982 A00000001-A99999999 Lawn-Boy F100R7268 1984 C00000001-C99999999 Lawn-Boy F100R7268 1985 D00000001-D99999999 Lawn-Boy F100R7270 1983 300000001-399999999 Lawn-Boy F100R7270AE 1983 B00000001-B99999999 Lawn-Boy F100R7271 1984 C00000001-C99999999 Lawn-Boy F100R7271AE 1984 C00000001-C99999999 Lawn-Boy F100R8035 1986 E00000001-E99999999 Lawn-Boy FR8035AE 1986 E00000001-E99999999 Lawn-Boy FR8035B 1986 E00000001-E99999999 Lawn-Boy FR8237 1978 800000001-899999999 Lawn-Boy F140R8237 1979 900000001-999999999 Lawn-Boy F140R8237 1980 000000001-099999999 Lawn-Boy F140R8237 1981 100000001-199999999 Lawn-Boy F141R8237 1982 A00000001-A99999999 Lawn-Boy F141R8237AE 1978 800000001-899999999 Lawn-Boy F140AER8238AE 1979 900000001-999999999 Lawn-Boy F140AER8238AE 1980 000000001-099999999 Lawn-Boy F140AER8238AE 1981 100000001-199999999 Lawn-Boy F140AER8238AE 1982 A00000001-A99999999 Lawn-Boy F140AER8238AE 1983 B00000001-B99999999 Lawn-Boy F140AER8238AE 1984 C00000001-C99999999 Lawn-Boy F140AER8240 1983 B00000001-B99999999 Lawn-Boy F140R8240AE 1983 B00000001-B99999999 Lawn-Boy F140AER8241 1984 C00000001-C99999999 Lawn-Boy F140R8241AE 1984 400000001-499999999 Lawn-Boy FR8242AE 1986 E00000001-E99999999 Lawn-Boy FS19ZPN 1989 H00000001-H99999999 Lawn-Boy FS19ZPNA 1990 J00000001-J99999999 Lawn-Boy FS19ZPNB 1991 K00000001-K99999999 Lawn-Boy FS20BSR 1989 H00000001-H99999999 Lawn-Boy FS20ESR 1989 H00000001-H99999999 Lawn-Boy FS20ZPR 1989 H00000001-H99999999 Lawn-Boy F


Page 23 of 23

Model Year Serial Range Engine Manuafacturer Engine Model NumberS20ZSR 1989 H00000001-H99999999 Lawn-Boy FS21BSN 1989 H00000001-H99999999 Lawn-Boy FS21BSNA 1990 J00000001-J99999999 Lawn-Boy FS21BSR 1991 K00000001-K99999999 Lawn-Boy FS21ESN 1989 H00000001-H99999999 Lawn-Boy FS21ESNA 1990 J00000001-J99999999 Lawn-Boy FS21ESR 1991 K00000001-K99999999 Lawn-Boy FS21ZPM 1991 K00000001-K99999999 Lawn-Boy FS21ZPN 1989 H00000001-H99999999 Lawn-Boy FS21ZPNA 1990 J00000001-J99999999 Lawn-Boy FS21ZPNB 1990 J00000001-J99999999 Lawn-Boy FS21ZPR 1991 K00000001-K99999999 Lawn-Boy FS21ZSM 1989 H00000001-H99999999 Lawn-Boy FS21ZSM 1991 K00000001-K99999999 Lawn-Boy FS21ZSN 1989 H00000001-H99999999 Lawn-Boy FS21ZSNA 1990 J00000001-J99999999 Lawn-Boy FS21ZSR 1991 K00000001-K99999999 Lawn-Boy FSB-12 1959 900000001-999999999 Lawn-Boy C12AASB-13 1960 000000001-099999999 Lawn-Boy C12AASB-13 1961 100000001-199999999 Lawn-Boy C12AASSI 1981 100000001-199999999 Piston Powered Products (Ryobi)SSIA 1984 400000001-499999999 Piston Powered Products (Ryobi)SSIB 1985 500000001-599999999 Piston Powered Products (Ryobi)SSIB 1986 600000001-699999999 Piston Powered Products (Ryobi)SSII 1981 100000001-199999999 Piston Powered Products (Ryobi)SSIIA 1984 400000001-499999999 Piston Powered Products (Ryobi)SSIIB 1985 500000001-599999999 Piston Powered Products (Ryobi)SSIIB 1986 600000001-699999999 Piston Powered Products (Ryobi)

SECTION 3 - ENGINE DIAGNOSIS D I A G N O S I S I S I M P O R T A N T

Remember the last time you didn't feel just right, and went to see your doctor? Did he say "hello," then rush you right into the operating room and remove your appendix? If he did, he would probably soon lose most of his patients, in one way o r another. What he probably did first was to set you down and ask you some questions. Then he probably made a few tests, such as temperature, blood pressure, etc., before arriving at any sort of diagnosis. With the results, he could make more specific tests and arrive at an accurate diagnosis before treating you. Because of your doctor's training and careful diagnosis, you haveconfidence in him.

You, as a service repairman, can instill confidence in your customers by a careful diagnosis of their mower troubles. Diagnosis is a talent, a talent which must be learned and continually practiced.

A N Y E X P E R T A T D I A G N O S I S FOLLOWS A SET PROCEDURE

Your doctor takes your temperature, checks your pulse, heart, etc. before attempting a diagnosis. A service repairman must also follow a set procedure in trouble diagnosis to make fast and accurate repairs.


OBTAIN GENERAL PRELIMINARY INFORMATION

1.. Fill out a brief report with the-customers help. Put this information on the repair ticket which will be attached to the mower. Un- less the failure is obvious, this may help the mechanic later on, especially if work is delayed for several days.

2. Have the customer look over the mower with you. Note obvioH damage, removal or alteration of safety equipment such as trailing shield, toe guard, interlock cable etc. on therepair ticket in the presence of the customer. This may protect you if any questions arise later as to the responsibility for damage.

3. Find out how the mower is used:

Was it used in a small or large yard, at home only o r often lent out? Was it used on level, clean lawns, rough ground, vacant lots, heavy weeds, etc ?

4. Find out what kind of gasoline and oil is used. Pull the engine through with starter rope, and if it binds o r is dry internally (indicating lack of oil) show the customer.

5. If damage is apparent, find out how damage occurred,

W I T H T H I S I N F O R M A T I O N , Y O U R M E C H A N I C C A N P R O C E E D W I T H SPECIFIC TESTS

3-2 . . . . . , . . . . , . , . . , . . . . . . . . . . . . . , . . . . . . . . . . SERVICE BULLETIN REFERENCES REVISED 1977

Train your mechanics in set diagnosis procedures. Normally, diagnosis takes very little time in the beginning, and will probably save a great deal of time in eliminating unnecessary repair work. 1. BEFORE YOU TRY TO START ENGINE a. Be sure there is clean fuel in tank. b. Be sure gas cap vent and fuel shut-off valve are open. c. Be sure ON-OFF Switch is in ON position. d. Check ON-OFF switch lead - must be connected to switch.

2. CHECK COMPRESSION a. With ON-OFF switch in OFF position, pull engine through several times with starter. Feel for compression as you pull engine through. If engine spins very easily, it has little (if any) compression. With little compression, there will be little o r no power.

b. If engine resists pull of starter rope, it has compression. If you spin an engine with good compression fast enough, you can hear the carburetor sucking air--and kick- back noise.

c. While checking for compression, also listen for any scraping or squeaking internal noises. These noises indicate piston and cylinder scoring. If you hear such noises, do not t r y to start the engine, but turn to Section 8, Engine Repair Procedure,

3. I G N I T I O N CHECK a. Take out the spark plug and examine it. Be sure that the electrodes are clean and the gap is .O25" for D-400 SERIES, ,035'' for D-600 SERIES, and .035" for "F" SERIES. Check the porcelain, If it is cracked, the plug won't fire. If the end of the plug i s wet, at least you know fuel is getting through. As a further check to see that fuel is getting through, place your thumb over the spark plug hole, and pull the starter cord several times. Your thumb should be wet with fuel,

b. Check spark plug using special tool part no. 426814. If spark plug tool is not available, remove plug from the cylinder, hold it approximately 1/4"-3/16" away from engine, pull the starter cord several times and check the spark between the plug and ground. The spark should be hot blue and snapping. A weak spark is orange, and makes little, if any, noise.

C. If there is no spark, or a very weak spark, ALWAYS try another plug. It only takes a few minutes, and these few minutes could save you hours. BE SURE YOU USE THE RIGHT

d. If the new plug won't fire, remove the plug from the lead wire and place a bolt in the rubber hood, 'making contact with the spring terminal. Hold the bolt head 1/4"-3/16" away from a metal part of the engine o r housing, and pull starter cord several times. A good spark should jump the gap.

e. If you don't get a spark at this point then you have ignition problems. Refer to Section 6 for detailed service information.

PLUG - DON'T GUESS.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 REVISED 1977

4. CARBURETION D IAGNOSIS

If you have a spark at the plug (even though a weak spark), check to see that the fuel mixture is getting into the combusion chamber.

a. Remove spark plug from cylinder.

SAFETY WARNING

ALLOW 10 SECONDS TIME BEFORE REMOVING SPARK PLUG LEAD. THIS ALLOWS CHARGE IN CD PACK TO LEAK OFF.

b. Place finger over spark plug hole in cylinder and pull starter rope several times.

c. If fuel mixture is entering cylinder your finger will be wet. If fuel is not entering cylinder refer to Section 4 for complete carburetor repair.

I M P O R T A N T

Always check fuel tank - make sure it is clean and contains no water. Instruct customer in use of correct fuel mixture - Refer to Operator’s Manual.

Air filter element must be clean. Check for dirt or obstructions in carburetor throat.

D-400 Series - Turn carburetor adjusting knob counterclockwise two turns from seat to make sure needle is open.

D-600 Series - Check atmospheric pressure adjustment - Correct normal setting is 1-1/2 turns from closed setting.

“F” Series - Check atmospheric pressure adjustment - Correct normal setting is 1/2 turn from closed setting.

D-600 Series - Check atmospheric pressure adjustment - normal pre-setting is 1-1/2 turns from closed setting.

“F” Series - Check atmospheric pressure adjustment - normal pre-setting is 1/2 turns from closed setting.

“F” Series - Fuel flow needle valve adjustment - normal pre-setting is 2 turns from closed setting.

Check fuel line to see if fuel is flowing into carburetor.

EXHAUST PORT CLEANING

If your checks have indicated that the engine has good spark, fuel flow and compression, yet engine won't run, o r "4-cycles," (ignition every other revolution) check the following:

EXHAUST PORT CLEANING Loss of engine power can be attributed, in many cases, to restricted exhaust ports. This restriction, results from a build-up of carbon deposits. Therefore, the muffler plate should be removed every 50 hours of operation o r at the end of the mowing season and the exhaust ports checked for carbon accumulation. This routine maintenance check is not only of vital importance to eliminate loss of engine power, but to eliminate particles of carbon from breaking away, entering the powerhead and causing piston scoring.

NOTE

Using LAWN-BOY 2 cycle oil in the required amount will minimize carbon build-up. Most oil is not made for burning and therefore, results in heavy accumulation of carbon.

NOTE

Replace blade nut o r bolt if removed o r installed MORE THAN FOUR times.

SAFETY WARNING: WHEN REAS- SEMBLING METAL MUFFLER COVER, ASSEMBLE FASTENERS

GAGE PREVIOUSLY FORMED

STALLATION AS THE SCREW WILL FORM A NEW SET OF WEAKER

ALLY STRIP AND THE SCREW MAY BECOME A THROWN OBJECT.

(SCREWS) WITH FINGERS TO EN-

THREADS. DO NOT FORCE REIN-

THREADS WHICH MAY EVENTU-

TORQUE TO 140-170 INCH LBS.

SAFETY WARNING: TO PREVENT

NECT AND REMOVE SPARK PLUG PRIOR TO REMOVING MUFFLER.

STARTING OF ENGINE, DISCON-

To clean exhaust ports, tip mower on its side and secure in this position. Remove nuts securing muffler cover to muffler plate and remove muffler cover. On some models the blade, blade stiffener, and adapter plate must be removed prior to removing muffler plate.

Pull starter rope slowly until piston covers the exhaust ports. Using a 3/8 inch diameter dowel, insert dowel into ports to break away carbon. Place mower in upright position and pull starter rope several times to blow out carbon. Clean muffler cover and cover plate and re-secure cover plate to muffler plate. If it was necessary to remove blade, torque blade nut to 50 ft . lbs. Torque blade bolt to 30-32 f t . lbs. Replace spark plug and reconnect high-tension lead.

SERVICE BULLETIN REFERENCES . . . . . . . . . . REVISED 1978 . . . . . . . . . . . . . . . . . . . . . . . . 3-5

ENGINE DIAGNOSIS

Upper and lower crankshaft seals - Worn seals may develop leaks, which permit air to enter o r leave crankcase, impairing the compression and vacuum cycle. Upper (armature plate) seal on. later "D" model engines is a spring loaded type. This provides more positive sealing to prevent oil leaking past and fouling breaker point.

Gaskets - Defective gaskets can allow a i r leakage in addition to oil leakage. The results are the same as leaky seals.

Screws and bolts - Inspect for tightness. Loose screws or bolts can also permit air to enter or leave, impairing the compression and vacuum cycle.

Major castings - Check for porosity in the carburetor, crankcase, cylinder, and magneto plate. Porosity results from a defect in the casting process, and is indicated by tiny a i r holes in the casting. This condition also results in air leaks. In some cases, the use of a penetrating ink will reveal hidden holes.


r

t SERVICE BULLETIN REFERENCES

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. . . . 3-7

I L a

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3-8 . . . . .

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. . . . . SERVICE BULLETIN REFERENCES

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W

SERVICE BULLETIN REFERENCES . . .

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. . . . . . . . . .

. . . . . 3-9

L

. . . . . . . . . .

, . . . , , . . . .

SERVICE BULLETIN REFERENCES . .

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"F" SE SECTION 3 ENG

ENGINE DIAGNOSIS

Loss of engine power may be attributed, in many cases, to improper sealing of the crankcase halves and/or incorrect torque applied to the crankcase cover to crankcase mounting screws. A poor seal results in air and oil leakage, impairing the compression and vacuum cycle. Refer to Sec- tion 8 for correct installation of crankcase halves.

INTAKE PLUGS

Check for worn or damaged upper and lower main seals. Worn seals may develop leaks, which permit air to enter or leave crankcase, impairing the compression and vacuum cycle.

SERVICE BULLETIN REFERENCES . . . . . . . . . . .

DIAGNOSIS

Check (4) intake plugs for possible leaks. Use special tool part no. 609964 to correctly install intake plugs.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11

"F" SERIES (Cont.)

SELF - PROPELLED MODELS

Check gear housing gasket -- defective gaskets can allow air or oil leakage.' This causes same results as leaky seals.

Check power take-off shaft seal for damage or wear. A worn or damaged seal results in oil leakage and lower crankcase pressures.

3-12 . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

“F” SERIES (Cont.)

EXHAUST PORT CLEANING

Excessive carbon deposits present in the exhaust ports and muffler baffle cause additional wear to engine parts and create a noticeable power loss. Approximately every 50 hours and at the close of the mowing season check for excessive carbon accumulation in exhaust ports and muffler baffle. This routine maintenance check is not only of vital importance to eliminate loss of engine power, but to eliminate particles of carbon from entering the cylinder, causing piston scoring.

NOTE

Using Lawn-Boy Special lubricant in the required fuel/oil mixture will minimize carbon build-up. Most oil is not made for burning and therefore, results in heavy accumulation of carbon.

MUFFLER BAFFLE AND EXHAUST PORTS

SAFETY WARNING

TO PREVENT STARTING OF EN- GINE, DISCONNECT SPARK PLUG WIRE AND REMOVE SPARK PLUG PRIOR TO REMOVING MUFFLER.

To clean muffler baffle and exhaust ports, tip mower on its side. Remove the blade nut, blade, blade stiffener (washer on 21” models) and blade adapter hub. The hub is tapered to fit the taper of the crankshaft. Tap the hub with a fiber hammer to loosen it from the crankshaft. Remove three bolts securing crankshaft support and muffler to muffler plate. Remove crankshaft support and muffler baffle.


"F" SERIES (Cont.)

Using a 3/4 inch diameter wooden dowel remove carbon deposits from opening in muffler baffle and muffler tube. SAFETY WARNING

WHEN REASSEMBLING MUFFLER COVER, ASSEMBLE FASTENERS

GAGE P R E V I O U S L Y FORMED THREADS. DO NOT FORCE REIN- STALLATION AS THE SCREW WILL FORM 'A NEW SET OF WEAKER THREADS WHICH MAY EVENTU- ALLY STRIP AND THE SCREW MAY BECOME A THROWN OBJECT.


TORQUE T O 140-170 INCH LBS.

Reinstall adapter hub, blade stiffener (washer on 21" models), blade and blade nut. Torque blade nut to 50 ft. lbs. Replace spark plug and reconnect high-tension lead.

Pull starter handle slowly until piston covers the exhaust ports. Using a 7/16 inch diameter wooden dowel, insert dowel into ports to loosen carbon deposits. DO NOT

STRUMENT. Place mower in operating position and pull starter handle several times to blow out carbon deposits. Reinstall muffler and crankshaft support to mower. Use special tool part no. 609968 to correctly align crankshaft support.

DAMAGE PISTON BY USING METAL IN-

3-14 . . . . . . . . . . . . . . . . . . . . . . . . REVISED 1978 . . . . . . . . SERVICE BULLETIN REFERENCES

''F" SERIES (Cont.

I

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t

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SERVICE

BULLETIN

REFERENCES . .... ..... ... . . . . . .

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3-16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SERVICE BULLETIN REFERENCES

\

PRINCIPLES OF C A R B U R E T I O N

The job of the carburetor is to combine liquid gasoline with air to form an explosive gaseous mixture. Gasoline in a liquid form is not explosive. BUT IF ENOUGH GASOLINE VAPOR COMBINES WITH AIR, A VERY EXPLOSIVE MIXTURE WILL RESULT.

atomizer, or an insecticide gun.- Even a sneeze is comparable, where air from the large lung area is ejected through the smaller nose and mouth openings, picking up secreted liquids and coming out in the form of a vapor.

SERVICE BULLETIN REFERENCES . . . , . . . , . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . 4-1

ENGINE FUEL S Y S T E M

NOZZLE - Connects fuel reservoir in float bowl to carburetor throat.

ADJUSTING NEEDLE - Meters flow of fuel through nozzle.

FUEL LINE - Connects tank to carburetor.

FLOAT VALVE - Pro- * vides constant fuel

level in float bowl.

ENGINE FUEL S Y S T E M

The carburetor starts i ts action and operates as follows:

PRESSURE IN CRANKCASE

VACUUM IN CRANKCASE

4. The carburetor throat is a Venturi. tube, large at each end with

1. The crankshaft rotates when the starter rope is pulled.

2. The rotating crankshaft moves the piston up and down in the cylinder. This creates pressure and vacuum alternately in the crankcase.

3. The vacuum created by movement of the piston upward in the cylinder opens a reed valve - then air rushes through the throat of the carburetor.

a smaller center passage. When air rushes through this tube, the air pressure at the center is less.

5. By inserting a tube from the carburetor float bowl into this center area, the difference in air pressure will force fuel up through this tube, where it is picked up by, and mixed with,

LOW PRESSURE AREA

AIR PRESSURE

the air.

6. Turbulence around the throttle disc helps to mix the fuel and air.

7. As fuel and air mixture enters the crankcase through the reed valves, it is near a gaseous state. The engine, when cold, will not vaporize the mixture completely. As the engine warms up, the mixture is heated in the crankcase and becomes a consistently even gas.


FUEL SYSTEM I N S P E C T I O N

SAFETY WARNING

GASOLINE IS EXTREMELY FLAMMABLE AND HIGHLY EXPLOSIVE UNDER CER- TAIN CONDITIONS. ALWAYS STOP ENGINE, AND DO NOT SMOKE OR ALLOW OPEN FLAMES OR SPARK WHEN REFUELING.

Start your inspection with the fuel used in the 2-cycle engine. Make sure your customer knows the why and how of fuel mix preparation. The supply can, from which fuel is poured into the engine tank, should have a water and dirt retardomg screen. Rust in the tank is caused by water poured into the tank from the supply can o r by water accumulated INSIDE the tank through CONDENSATION. Later D Series Deluxe models a re equipped with a plastic gas tank assembly eliminating condensation, rust and are not affected by fuel mixture. Ex- treme changes in temperature can cause heavy condensation ,in a closed fuel tank that is NOT FULL. ALWAYS TELL CUSTOMERS TO KEEP TANKS FULL WHEN MOWER IS NOT IN USE, DURING THE MOWING SEASON. During storage, the tank should be empty, and the mower stored in an area not subject to extreme temperature change.

A SAFETY WARNING

TO PREVENT POSSIBLE EXPLOSION OR IGNITION O F VAPORIZED FUEL, DO NOT STORE MOWER WITH FUEL IN TANK OR CARBURETOR IN ENCLOSURE WITH OPEN FLAME. (EXAMPLE: FURNACE OR WATER HEATER PILOT LIGHT.)

If you find water and/or dirt and rust in the tank, show the customer how a double screen funnel or a flexible nozzle with screen will help.

4-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . , , . . . SERVICE BULLETIN REFERENCES REVISED 1977

FUEL TANK VENTING

D-400 SERIES FUEL SYSTEM I N S P E C T I O N

Fuel tanks must be vented to prevent vacuum forming and stopping flow of fuel. Tank caps have a plain vent hole. A closed vent will create a vacuum in the tank a s fuel is used - the engine will run a few minutes and stop. In a few minutes the vacuum will decrease and the engine can be started again, but it will stop again in a few minutes. The vent hole can become clogged with dirt., inspect and clean ,as required.

SHUT-OFF VALVE The screen assembly or the shut-of€ valve can become clogged. This can be checked easily by removing the fuel hose, opening the valve and observing for fuel flow through the valve. Replace the valve and screen assembly if gummed up, rusted, or if packing is damaged.

NOTE Shut-off valve should be open and packing nut loose before screw- ing assembly into tank. Secure assembly to tank, then close valve and tighten packing nut. Wing should turn easily, but snugly.

FUEL L I N E Inspect the fuel line, If cracked, spongy, or otherwise not f i t for good safe use, replace. DON’T TWIST FUEL LINE - IN- SERT ON CONNECTIONS WITH FINGERS, NOT PLIERS.

SAFETY WARNING DO NOT SUBSTITUTE WITH INFE- RIOR FUEL HOSE WHICH MAY

TURE DETERIORATION. LEAKAGE OF FUEL MAY CAUSE AN EXPLO- SION AND/OR FIRE.

CAUSE LEAKAGE FROM PREMA-

AIR FILTER If engine is flooded, fuel can drain back into filter. As filter becomes saturated, incoming air picks up more fuel, causing greater flooding. A puckered filter will allow air and dirt to bypass filter. Make certain that filter covers cup area. If oiled, properly, filter is very efficient. First wash out with hot, soapy water. Wring out and dry completely, then apply 10 to 15 drops of oil. Squeeze several times to distribute oil. If engine “smokes” for no apparent reason, check filter for flooding and a rich running condition.

Later D-400 Series models have a plastic air cleaner. To remove grasp the cover lip and pull back o r fold down as required.

NOTE Reinstall filter in the same position which it was removed.

SERVICE BULLETIN REFERENCES . . . . . . . . , . , . . . , . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 REVISED 1977

D-400 SERIES FUEL SYSTEM INSPECTION

NOTE Some later model D-400 engines a re equipped with the D-600 Series fuel system. A thorough visual inspection will determine the fuel system used on the engine.

FLOAT VALVE

The float valve consists of a needle and seat assembly, activated with a float in the float bowl. The needle is steel with rubber tip and the seat brass, materials which will not readily adhere together. The needle rests on the float arm, (held in place by a spring clip on later models).

Operation is automatic. When the float bowl is empty, the float rests on the bottom of the bowl. As fuel enters bowl of carburetor, the float rises, moving needle into seat and shutting off fuel. As the engine uses fuel, the float drops slightly, allowing more fuel to enter bowl, maintaining a constant fuel level in bowl.

The needle and seat must be replaced as an assembly. 'They a re matched to form a perfect seal.

Some of the problems you may encounter with the float valve

Cause

GUM IN FUEL

SPRING WIRE CLIP COMES OFF

NEEDLE AND SEAT NOT MATCHED

FLOAT ARM NOT SET RIGHT

PIVOT PIN CORRODED OR BENT

FLOAT STRIKING NOZZLE

VARNISH OFF FLOAT

Effect

Stops up openings

Needle may stick shut

Fuel supply can't be shut off from float bowl

Set too high - carburetor

Set too low - carburetor floods

starves

Float sticks

Float sticks

Float soaks up fuel, changing floating characteristics

are a s follows:

Remedy

*Clean out carb. with solvent

Replace Clip

Replace Needle and Seat as an Assembly

Set correctly

Set correctly

Replace Pin

Replace Float

*Replace Float

*Never allow a strong solvent to come in contact with the float. The cork float is coated with an epoxy sealer. If the solvent removes the epoxy, the float will absorb gasoline and its floating characteristics will change.

4-6 . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

REVISED 1977

D - 4 0 0 SERIES CARBURETOR ADJUSTMENTS

NEEDLE ADJUSTMENT

To adjust needle, turn adjusting knob clockwise until needle seats lightly; DO NOT FORCE NEEDLE DOWN TOO TIGHT, SINCE YOU MAY DAMAGE NEEDLE OR SEAT IN NOZZLE AND MAKE FURTHER ADJUST- MENT DIFFICULT.

Then open needle two turns. Start engine. If engine begins to die, open carburetor adjusting knob by turning counterclockwise. If engine runs roughly, close knob by turning clockwise until engine smooths out. Let engine run for about 5 minutes to warm up. Close adjusting knob slowly until engine begins to die, then open adjusting knob 1/4 to 1/2 turn.

Carburetors on earlier "D" 400 model en- On later "D" 400 model engines the low gines also contain a slow speed adjustment. speed needle adjusting valve has been re- The correct setting for this adjustment is 1 placed with a fixed jet. This jet is pressed turn open. If an engine runs ROUGH or into the low speed passage and the passage "HUNTS" at the "low" speed setting it can opening is sealed with a lead shot.

adjustment. be leveled out by opening, o r closing this

SERVICE BULLETIN REFERENCES . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7

D-400 SERIES .CARBURETOR SERVICING

FLOAT SETTING Remove float bowl and gasket. Invert carburetor. With float arm resting on float valve needle, the top of float should be 15/32 inch above edge of carburetor body. To adjust; bend metal a rm with needle nose pliers.

NOTE

DO NOT attempt to bend by applying pressure to cork float.

Carburetor servicing consists of inspection, cleaning, adjustment, and replacement of faulty parts.

To remove carburetor from engine, carburetor and reed plate must be removed as an assembly,. and reed plate removed from carburetor.

Carburetor service assemblies include 2 thread forming screws. The reed plate mounting flange on the carburetor is drilled but not tapped. These screws form a very tight fit eliminating the possibility of screws vibrating loose during engine operation.

MOUNTING HOLES

UNTAPPED THREAD FORMING SCREWS

The metal carburetor body can be cleaned with a good solvent and blown dry with air, EXCEPT THE CORK FLOAT. A solvent will remove the varnish from the float. Inoperative floats should be replaced. DO NOT DRY CARBURETOR PARTS WITH A CLOTH, because lint may stick to the parts and cause trouble in the reassembled carburetor.

Inspect valve needles for grooves or other defects. If grooved or otherwise defective, replace. Use a magnifying glass in the inspection. Tiny scratches or worn surfaces affect the operation.

4-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

D-400 SERIES CARBURETOR SERVICING

The reed plate can be cleaned with solvent with the rest of the carburetor. Be careful in handling reeds, so as not to distort them. The

or otherwise damaged reeds cannot be repaired. Check the reed plate for warpage. DO NOT USE COMPRESSED AIR ON REEDS, The rough edge of the reed should be away from the plate.

MACHINED SURFACE

reeds must lie flat against the reed plate to form a perfect seal. Bent

Maximum clearance allowed between reed tip and reed plate is .015. If clearance exceeds this, reeds must be replaced.


D-400 SERIES CARBURETOR S E R V I C I N G FUEL NOZZLE FILTER The nozzle filter will provide a secondary filtering device to minimize the possibility of "fuzz" or other minute particles getting into the carburetor area, which causes engine stalling. Prior to installing nozzle fi l ter clean carburetor, high speed nozzle, fuel tank, fuel shut-off valve and filter assembly. High speed nozzle must be removed to clean it properly.

Install filter on the nozzle firmly.

DO NOT slide neoprene ring over fuel passage hole.

Hold float up and lift bowl carefully in place. (For easier installation, take carburetor off and turn upside down.)

FILTER

PART NO. 607637

L- FUEL FILTER IN PLACE ON NOZZLE

r

D- 400 SERIES ENGINE CARBURETOR SERVICING H INTS LOW SPEED NEEDLE ASSEMBLY

LEAD SHOT

CARB VENTURI FUEL INTO


D - 4 0 0 ENGINE CARBURETOR S E R V I C I N G H I N T S ( C O N T )

D-400 SERIES CARBURETOR THROTTLE S H A F T IS SPLIT FOR THROTTLE DISC MOUNTING.

FLATTED SIDE

7/3 2

THREADS SLOT

THE SHAFT S IZE IS LARGER THAN “C” ENGINE THROTTLE SHAFTS.

ALWAYS PLACE CORRECT TENSION ON

STALLING. THROTTLE SHAFT SPRING WHEN IN-

THROTTLE SHAFT

CARBURETOR BODY

HOOK END IN CARBURETOR BODY AND ADD TENSION BY TURNING SPRING 1/2 - 3/4 TURN AND HOOK ON THROTTLE SHAFT ARM.

ENGINE S U R G I N G DUE TO C A R B U R E T I O N Surging explanation: High to Low R.P.M. constantly,

1. A burr on the throttle shaft arm which holds governor rod in place can cause a drag. This can contribute to surging. Repair - clean off burr, check governor rod for wear.

2. Throttle shaft may wear causing shaft and/or throttle disc to bind. Replace shaft and disc.

3. Improper adjustment.


FUEL INFORMATION

NOTE

Your LAWN-BOY uses a two cycle engine. This means the oil and gasoline must be mixed together. Fail- ure to use the proper fuel mixture will result in serious damage to the engine.

GASOLINE - Use automotive regular grade with a minimum of 89 pump octane, “No-Lead” or “lead free” gasoline of 86 pump octane is satisfactory if owner wishes to use it. DO NOT USE GASOHOL OR OTHER GASOLINES THAT CONTAIN ETHANOL OR METHANOL.

LUBRICATION (OIL) - Use LAWN-BOY 2 cycle oil available from your LAWN-BOY dealer. If not readily available, use a good grade of two cycle oil from a reputable oil company. DO NOT USE AUTOMO- TIVE OILS.

FUEL MIXTURE

Use clean container. Mix thoroughly. DO NOT mix fuel directly in mower fuel tank.

CORRECT FUEL MIXTURE (CURRENT MODELS) Use LAWN-BOY SPECIAL 2-cycle oil. M i x one full can with 2 gallons (U.S.) of gasoline.

NOTE

Follow instructions on can.

If you use OTHER 2-CYCLE oil, mix 8 ounces (U.S.) with 1 gallon (U.S.) of gasoline.

(OLDER MODELS) Mix one full can of Lawn-Boy 2-cycle oil with 1 gallon (U.S.) regular gasoline. Refer to owner’s manual for instructions.

SAFETY WARNING

GASOLINE IS EXTREMELY FLAM- MABLE AND HIGHLY EXPLOSIVE UNDER CERTAIN CONDITIONS. ALWAYS STOP ENGINE, AND DO NOT SMOKE OR ALLOW OPEN

FUELING. FLAMES OR SPARK WHEN RE-

4-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES REVISED 1983

D-600 SERIES FUEL SYSTEM

PRINCIPLES OF CARBURETION

NOTE Some later model D-400 engines are equipped with the D-600 series fuel system. A thorough visual inspection will determine the fuel system used on the engine.

SAFETY WARNING DO NOT SUBSTITUTE WITH INFE- RIOR FUEL HOSE WHICH MAY CAUSE LEAKAGE FROM PREMA- TURE DETERIORATION. LEAKAGE

SION AND/OR FIRE. OF FUEL MAY CAUSE AN EXPLO-

The carburetor used on Solid State (C.D.) ignition engines is automatic. No fuel adjustments are necessary, to regulate fuel intake. A single, metered jet allows the correct amount of fuel to mix with the incoming air which is regulated by a single adjusting needle that is explained on page 4-15 of this section. Adjustment must be changed when a significant change in altitude is encountered.

.

T

DRAIN VALVE

DJUSTMENT

FUEL CAP

GASKET

FUEL C A P

FUEL TANK VENTING

Fuel tanks must be vented to prevent vacuum forming and stopping flow of fuel. Tank caps will have a vent hole. A closed vent will create a vacuum in the tank as fuel is used - and eventually cause the engine to stop. In a few minutes the vacuum will decrease and the engine can be started again, but it will stop again in a short period of time. The vent hole can become clogged with dirt. Check vent hole before each operation and clean if necessary.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . .

FUEL TANK F I L T E R

U

FUEL TANK

GASKET

C L I P

SHUT-OFF VALVE

The fuel tank screen assembly or the shut- off valve can become clogged. This can be checked easily by removing the fuel hose, opening the valve and observing for fuel flow through the valve. Replace the fuel shut-off assembly if damaged.

Shut-off valve is secured to fuel tank with a spring clip; exercise care when re-installing to fuel tank.

. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13 REVISED 1977


AIR FILTER

AIR VENT PASSAGE

A I R FILTER ASSEMBLY AIR FILTER

-ELEMENT

If engine is flooded, fuel can drain back into filter. As filter becomes saturated, incoming air picks up more fuel, causing greater flooding. A puckered filter will allow air and dirt to bypass filter. Make certain that filter covers cup area. If oiled properly, filter is very efficient. First wash out with fuel, then apply 10 to 15 drops of oil. Squeeze several times to distribute Reinstall filter in the same position oil. If engine “smokes” for no apparent which it was removed to prevent reason, filter may be saturated with fuel imbedded particles in intake side mix o r may need cleaning. from entering carburetor. Install

air filter case correctly. Hinge on To remove grasp the cover, loosen snap and bottom. If installed upside down the fold cover down. air vent passage will be blocked.

NOTE

Examine the primer system. Instead of into the float bowl chamber which forces lifting fuel up in the carburetor throat as in fuel into the carburetor venturi. the case with some D-400 series engine, the /-

pneumatic primer forces compressed air



1-1/2 TURNS SETTING

\

AIR ADJUSTMENT

The carburetor is completely automatic. There are no adjustments to be made to regulate the amount of fuel entering the carburetor venturi. There is an atmospheric pressure adjustment that would have to be made if the engine is operating in very high o r very low altitudes.

All D-600 series and modular carburetors require a final adjustment of the altitude needle prior to putting the mower into service.

To adjust, proceed as follows:

1. Pre-set altitude needle 1-1/2 turns from seat.

2. Start engine and allow to run for 3 to 5 minutes to warm up.

3. Place speed control lever in LOW SPEED running position (2400-2600 R.P.M.)

4. Turn altitude needle clockwise until engine starts to "hunt," ''surge" or slow down.

5. Slowly turn altitude needle counterclockwise until engine is running smoothly. Allow engine to run for one or two min-

utes to make sure adjustment is not too lean.

6. Place speed control lever in HIGH SPEED running position (3100-3300 R.P.M.) Observe engine operation. If not running smoothly, turn altitude needle counterclockwise approximately 1/4 turn at a time to obtain proper engine operation.

7. After carburetor adjustment is completed, shut off engine. IMMEDIATELY attempt to restart engine. It should start within 2 pulls on starter handle. Check starting engine at both HIGH and LOW speed settings. If difficult to restart, turn altitude needle 1/8 to 1/4 turn counterclockwise to richen fuel mixture and obtain easy restarting.

DO NOT PRIME A HOT ENGINE.

NOTE

The governor will control the amount of fuel entering the engine. The purpose of the atmospheric pressure adjusting needle is to mix the right amount of fuel with the correct amount of incoming air.



AIR ADJUSTMENT ( Continued )

NOTE

In the closed position no air is entering the carburetor vent passage. Therefore, the float bowl pressure has been eliminated and the fuel supply to the carburetor venturi is cut off.

FLOAT AND VALVE

Examine float appearance. Should be glossy because of epoxy sealer. If dull in appearance, o r portions of epoxy has chipped away - replace.

NOTE

Do not clean float with any type of solvent or carburetor cleaner. Clean with standard fuel mix.

The float valve consists of a needle and seat assembly, activated by a float in the carburetor bowl. The steel needle is rubber tipped and the seat brass. This combination eliminates possible sticking and provides a perfect seal. The needle rests on float arm, held in place by a spring clip.

CLOSED SETTING

Operation is automatic. When float bowl is empty, float rests on bottom of bowl, As fuel enters bowl of carburetor, float rises, moving needle valve into seat and shutting off fuel. As engine uses fuel, float drops slightly, allowing more fuel to enter bowl, maintaining a constant fuel level in bowl.

Needle and seat must be replaced as an assembly. They are matched to form a perfect seal.

FLOAT

NEEDLEVALVE

DUMP VALVE ASSEMBLY

GASKET

NOTE: Check dump valve and gasket for distortion o r damage.



Some of the problems you may encounter with the float valve a re as follows:

Cause

GUM IN FUEL SPRING WIRE C LIP COMES OFF NEEDLE AND SEAT NOT MATCHED FLOAT ARM NOT SET CORRECTLY

PIVOT PIN CORRODED OR BENT FLOAT STRIKING NOZZLE VARNISH OFF FLOAT

Effect

Stops up openings Needle may stick shut

Fuel supply can't be shut off from float bowl Set too high - carburetor floods Set too low - carburetor starves Float sticks

Float sticks Float soaks up fuel, changing floating characteristics

BEND ARM HERE TO ADJUST

2

FLOAT ADJUSTMENT FLOAT SETTING Remove float bowl and gasket. Invert carburetor. With float arm resting on float valve needle, the top of float should be 15/32 inch above edge of carburetor body as shown. To adjust; bend float arm with long nose pliers.

DO NOT bend by applying pressure to cork float. Bend arm only by grasping with pliers.

THROTTLE SHAFT AND VALVE (DISC) SERVICING Early 1972 production models used plastic throttle shaft and snap-in disc. Later 1972 production models include bronze shaft, disc

*Clean out carburetor with solvent Replace clip

Replace needle and seat as an assembly Set correctly

Set correctly

Replace pin

Replace float *Replace float

and screw assembly part 681008. If replacement of shaft or disc is necessary, use this assembly number.

Disc is secured to shaft with screw as illustrated.

1. Remove reed plate assembly.



MACHINED SURFACE

ROUGH EDGE

2. Using needle nose pliers grasp throttle disc and remove disc from throttle shaft. Inspect disc for wear or burrs. Replace if necessary with shaft, disc and screw assembly part no. 681008.

3. Remove '"E" ring and slide throttle shaft from carburetor body. Inspect plastic throttle shaft for wear and replace if required with shaft, disc and screw assembly part no. 681008.

4. Reassemble in reverse order making sure small hole in throttle disc is installed facing reed plate assembly.

NOTE

Always place correct tension on throttle shaft spring when installing. Hook end in carburetor body and add tension by turning spring 3/4 turn and hook on throttle shaft leaf as illustrated on page 4- 11.

REED PLATE SERVICING

1. Reed plate assembly may be cleaned with same solvent used to clean carburetor. Exercise care in handling reeds, so as not to distort them. Bent or distorted reeds must be replaced.

2. Check for excessive clearance between reed tip and reed plate as illustrated. Maximum allowed clearance .015 inch.

3. Reeds must be installed with rough edge away from plate as shown.

NOTE

DO NOT USE COMPRESSED AIR TO CLEAN REED VALVES.

4-18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

MODULAR CARBURETOR

MODULAR CARBURETOR C O M P O N E N T S

The new modular carburetor was introduced in the 1975 D-600 ser ies engines and later production D-400 ser ies engines. This new carburetor is constructed of a special injection molded plastic material. The body and air filter chamber is a one-piece plastic assembly which "plugs" into the reed plate and is secured by a single screw. An O- ring installed between the carburetor and reed plate insures positive sealing. The float and fuel valve is also a one-piece assembly. This assembly rests on a spring located in the plastic float chamber. The spring provides vertical tension against the float forcing the fuel valve into the fuel inlet seat when the float chamber is full of fuel. As fuel enters a single metered jet it is mixed with incoming air to form the correct combustible mixture. The amount of fuel flow through the metering jet is regulated by the altitude needle. Adjustment procedure is same as earlier D-600 series carburetors. Refer to page 4-15 for adjustment procedure.

CARBURETOR BODY

"0" RING

FLOAT AND VE ASSEMBLY

PLATE ASSEMBLY

FLOAT CHAMBER

The governor will control the amount of fuel entering the engine. The purpose of the atmospheric pressure adjusting needle is to mix the right amount of fuel with the correct amount of incoming air.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19

.

MODULAR CARBURETOR

O- R I N G

An O-ring seals between the outer surface of the carburetor barrel and the inside diameter of the reed plate opening. The correct procedure to install the carburetor is to lubricate the O-ring in groove of the reed plate and "plug" in the carburetor.

When installing or removing carburetor from engine, the governor rod must be removed from the throttle arm.

CLEANING CARBURETOR altitude needle for damage, Check spring for damage - DO NOT BEND SPRING.

The carburetor assembly is injection molded Check gasket for cracks or wear. Always plastic. DO NOT clean using a standard use new gasket during reassembly. carburetor cleaner. Disassemble carbure-

grease solvent, dry and clean parts with compressed air - DO NOT dry using a If any part appears worn o r damaged, cloth, lint may block passages impeding replace it. To ensure proper float proper carburetor operation. action the float must be correctly in-

tor components, wash and clean using a good NOTE

stalled in float chamber (not binding). After cleaning, inspect all parts. Check After assembling float chamber to float and fuel valves for cracks or damage. carburetor body shake in a vertical Check throttle shaft, valve and spring for motion and listen for float move- smooth operation. Check float chamber for ment. If no sound (movement) is cracks or damage. Check dump valve and heard remove float chamber and re- gasket for distortion or damage. Check install correctly.

ALTITUDE CARBURETOR BODY NEEDLE

I

DUMP VALVE

FLOAT CHAMBER I


MODULAR

FLOAT SPRING The float spring is very critical in its operation.

It provides vertical pressure to the float and fuel valve forcing the fuel valve into the fuel inlet to stop the flow of fuel when the bowl has filled. Each end of the spring is located in a recessed area. The walls of these recesses provide guidance for vertical movement of the float and fuel valve. With- out these walled recesses the float and fuel valve would move laterally preventing the fuel valve from entering the fuel inlet seat squarely. Mowing at an angle such as a terrace could result in a carburetor flooding without these recesses.

DO NOT ATTEMPT TO CHANGE THIS SPRING DIMENSIONALLY. A specific free length dimension of 5/8" (.625 ± .030) is required to complete its function.

AIR FILTER ASSEMBLY

If engine is flooded, fuel can drain back into filter. As filter becomes saturated, incoming air picks up more fuel, causing greater flooding. A puckered filter will allow air and dirt to bypass filter. Make certain that filter covers cup area. If oiled properly, filter is very efficient. First wash out with fuel, then apply 10 to 15 drops of oil. Squeeze several times to distribute oil. If engine "smokes" for no apparent reason, filter may be saturated with fuel mix or may need cleaning. To remove grasp the detachable cover, loosen snap and fold cover down.

Reinstall filter in the same position which it was removed to prevent imbedded particles in intake side from entering carburetor.

PRIMER Examine the primer system. A pneumatic primer forces compressed air into the float bowl chamber which forces fuel into the carburetor venturi.

SERVICE BULLETIN REFERENCES . . . . . . . . . . . .

FILTER

~,

PRIMER ACTIVATED

. . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21 REVISED 1977

MODULAR CARBURETOR

FUEL AND PRIMER HOSE R O U T I N G

DO NOT SUBSTITUTE WITH INFE- RIOR FUEL HOSE WHICH MAY CAUSE LEAKAGE FROM PREMA- TURE DETERIORATION. LEAKAGE OF FUEL MAY CAUSE AN EXPLO- SION AND/OR FIRE.

PLASTIC CARBURETOR BODY

Proper hose routing requires the primer hose to be twisted counterclockwise approximately 1/2 turn around the fuel line. This will prevent the starter pulley from damaging the hoses. Exercise care when installing hoses.

Do not pull hoses taut in either direction. Leave sufficient slack in hoses to prevent contact with starter pulley.

METALCARBURETORBODY

Proper hose routing requires the hoses to be parallel with each other as shown. If twisted, i t is possible for hoses to be damaged by starter pulley. Exercise care when installing hoses.

1 COUNT

AROUN

4-22 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES REVISED 1977

D-600 SERIES FUEL SYSTEM TROUBLE SHOOTING

FUEL SYSTEM TROUBLE SHOOTING

1. Check for fuel in tank.

2. Remove air filter element.

3. If spurting of fuel is not visible.

4. Check function of primer bulb and hose.

5. If fuel is spurting from nozzle, when being primed, close fuel valve and remove carburetor and reed plate assembly. Re- move float chamber.

A. Fuel shut off (Tank) valve should be open.

B. Examine vent hole in gas cap. Make sure it is not restricted.

A. Watch nozzle in barrel of carburetor and push primer bulb down rapidly.

B. Fuel should spurt from top of nozzle.

A. Remove fuel line from carburetor to determine if fuel is flowing from tank thru tank filter, valve and hose.

B. If not, remove hose from tank valve. Turn valve on to determine if fuel is flowing from tank. If so, restriction is in fuel hose. Wash out in solvent and blow with compressed air.

A. Place finger over lower end of primer hose and press primer bulb. Resistance should be noted in bulb depression. Remove finger, there should be no resistance present when bulb is depressed.

B. Depress primer bulb and place finger over end of hose. The bulb should remain collapsed. If not, replace primer bulb and hose assembly.

A. Check float valve and seat assembly.

B. Check float level adjustment.*

C. Check to make sure movement of float and float arm is free.*

D. Check the throttle valve and shaft for freedom of movement.

E. Remove metering nozzle and check for restriction. *

F. Blow out altitude air vent passage.

G. Check setting and condition of reed valves.

*NOT APPLICABLE TO MODULAR CARBURETOR

SERVICE BULLETIN REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , 4-23 REVISED 1977

MODULAR CARBURETOR - UTILITY MODELS MODULAR CARBURETOR COMPONENTS

The new modular carburetor was introduced in the 1979 D-410 series engines on all utility models. This new carburetor is constructed of a special injection molded plastic material. The body and air filter chamber is a one-piece plastic assembly which “plugs” into the reed plate and is secured by a single screw. An O-ring installed between the carburetor and reed plate insures positive sealing. The modular carburetor has been redesigned featuring a new float chamber, gasket, float and carburetor body. A hinged type float of special cork material is sealed with an epoxy. During inspection, if . the float appears dull or dark in appearance it should be replaced. The float in this new modular carburetor is positioned differently than previous modular carburetors with the float upside down, and a float level adjustment requirement of 11/16 inches from carburetor body to top of float. As fuel enters a single metered jet it is mixed with incoming air to form the correct combustible mixture. The amount of fuel flow through the metering jet is regulated by the altitude needle.

NOTE

The governor will control the amount of fuel entering the engine. The purpose of the atmospheric pressure adjusting needle is to mix the right amount of fuel with the correct amount of incoming air.

NOTE

This new modular carburetor is also a Service replacement component for all previous D-Series modular carburetors. A Quick visual inspection will show you which modular carburetor is on the engine.

CARBURETOR BODY FLOAT

CHAMBER

4-24 . . . . . . . . . . . . . . . . . . . . . . . .

AIR FILTER ASSEMBLY

If engine is flooded, fuel can drain back into filter. As filter becomes saturated, incoming air picks up more fuel, causing greater flooding. A puckered filter will allow air and dirt to bypass filter. Make certain that filter covers cup area. If oiled properly, filter is very efficient. First wash out with fuel, then apply 10 to 15 drops of oil. Squeeze several times to distribute oil. If engine “smokes” for no apparent reason, filter may be saturated with fuel mix or may need cleaning.

To remove grasp the detachable cover, loosen snap and fold cover down.

a

NOTE

Reinstall filter in the same position from which it was removed to prevent imbedded particles in intake side from entering carburetor.

CARBURETOR REMOVAL

1. The modular carburetor is attached to the reed plate assembly by a single screw.

. . . . . . . . . . SERVICE BULLETIN REFERENCES

MODULAR CARBURETOR - UTILITY MODELS

During reassembly apply Lawn-Boy nut and screw lock part no. 682301 to threads of mounting screw.

2. Pull carburetor from reed plate assembly. Do not bend or damage the governor rod and/or throttle arm of the carburetor.

3. Check O-ring in reed plate assembly for damage. We recommend replacing O-ring every mowing season and during all tune-up operations.

O-RING

An O-ring seals between the outer surface of the carburetor barrel and the inside diameter of the reed plate opening. The correct procedure to install the carburetor is to lubricate the O-ring in groove of the reed plate and “plug” in the carburetor.

CARBURETOR

SERVICE BULLETIN REFERENCES . . . . . . . . . .

CLEANING CARBURETOR

The carburetor assembly is injection molded plastic.

Disassemble carburetor components, wash and clean using a good grease solvent, dry and clean parts with compressed air - DO NOT dry using a cloth, lint may block passages impeding proper carburetor operation.

After cleaning, inspect all parts. Check float and fuel valves for cracks or damage. Check throttle shaft, valve and spring for smooth operation. Check float chamber for cracks or damage. Check altitude needle and O-ring for damage. Check air vent passage which allows air to flow into the float chamber. If this passage should become restricted with dirt and/or debris the engine will not run correctly or stop running and flooding of carburetor will occur. Check gasket for cracks or wear. Always use new gasket during reassembly.

DO NOT clean using a standard carburetor cleaner.

AIR VENT PASSAGE I

NOTE

If any part appears worn or damaged, replace it. To ensure proper float action the float must be correctly installed in float chamber (not’ binding). Use needle nose pliers to secure hinge on float arm to pin.

. . . , . . . , . . . . . . . . . . . . . . . . 4-25

MODULAR CARBURETOR - UTILITY MODELS FLOAT AND VALVE ASSEMBLY

The float valve consists of a needle and seat assembly, activated by a float in the carburetor bowl. The steel needle is rubber tipped and the seat brass. This combination eliminates possible sticking and provides a perfect seal. The needle rests on float arm, held in place by a spring clip.

Operation is automatic. When float bowl is empty, float rests on bottom of bowl. As fuel enters bowl of carburetor, float rises, moving needle valve into seat and shutting off fuel. As engine uses fuel, float drops slightly, allowing more fuel to enter bowl, maintaining a constant fuel level in bowl.

Needle, seat and spring clip must be replaced as an assembly. They are matched to form a perfect seal.

Remove float bowl and examine float appearance. Float should be glossy because of epoxy sealer. If dull in appearance, or portions of epoxy have chipped away - replace float.

NOTE

Do not clean float with any type of solvent or carburetor cleaner. Replace it.

Some of the problems you may encounter with the float valve are as follows:

VARNISH

SPRING WIRE CLIP COMES OFF

NEEDLE AND SEAT NOT MATCHED

FLOAT ARM NOT SET CORRECTLY

PIVOT PIN CORRODED OR BENT

FLOAT STRIKING NOZZLE

VARNISH OFF FLOAT

LOOSE FLOAT HINGE CLIP ON PIVOT PIN

Effect

Stops up openings


Fuel supply can’t be shut off from float bowl

Set too high - carburetor floods - Engine runs rich

Set too low - carburetor starves - Engine runs lean

Float sticks

Float sticks

Float soaks up fuel, changing floating characteristics

Engine 4 cycles excessively when bumped or jarred

Remedy

Clean out carburetor with solvent

Replace clip

Replace needle and seat as an assembly

Set correctly

Set correctly

Replace pin

Replace float

Replace float

Crimp float hinge clip on pivot pin for tighter fit

4-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

MODULAR CARBURETOR = UTILITY MODELS FLOAT ADJUSTMENT

Float Setting

Remove float bowl and gasket. Invert carburetor. With float arm resting on float valve needle, the top of float should be 11/16 inch above edge of carburetor body as shown. Obtain measurements at two points at right angles to each other.

If adjustment is required; using needle nose pliers bend float arm as shown. DO NOT bend float arm by applying pressure to float, this will damage rubber tip on inlet needle.

Check hinge on float arm to be sure it is secured to pin. Use needle nose pliers and tighten hinge. The hinge should be clamped tight enough so that the pin will swivel in the carburetor instead of the arm turning on the pin.

NOTE

Tightening hinge to pivot pin will prevent inlet needle from not seating correctly when mower crosses uneven terrain. This condition is called “fluttering.”

Check pin clip on float arm by rotating carburetor sideways. If clip falls off float arm -- replace it.

SERVICE BULLETIN REFERENCES . . . . . . . . . .

MEASURE AT RIGHT ANGLES

FLOAT VALVE AND SEAT ASSEMBLY

NOTE

The float valve and seat must be replaced as an assembly. They are matched to form a perfect seal.

1. Remove hinge pin and remove float and valve. Remove spring clip securing valve to float arm.

. . . . . . . . . . . . . . . . . . . . . . . . 4-27

MODULAR CARBURETOR - UTILITY MODELS 2. Use a wide bit screwdriver to remove or install The pre-setting position is ONE TURN OFF THE

seat from carburetor body. When reinstalling SEAT. Use caution when installing this needle as the seat, tighten securely. Exercise care when damage may occur to the carburetor body or the tightening seat to prevent damaging the seat. needle if it is tightened excessively,

I I

ALTITUDE NEEDLE

The altitude needle has a rubber O-ring around it to seal the threads and prevent air from leaking through. It also serves as a locking feature to prevent the altitude needle from vibrating out of carburetor body.

4-28 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

"F" SERIES ENGINE FUEL SYSTEM

FUEL SYSTEM COMPONENTS AND THEIR FUNCTION

FUEL FILTER - Fil- PNEUMATIC PRIMER ASSEMBLY te r s out dirt and water, Forces compressed air into the allowing only clean fuel float chamber which forces to enter fuel line. into carburetor venturi.

AIR VANE GOVERNOR and closes

throttle, controlling engine r.p.m.

FUEL TANK Stores VENTED FUEL CAP

AIR FILTER - Keeps dirt from entering carburetor with air.

VALVES - Permit fuel mixture to THROTTLE DISC - FLOAT BOWL - Res- enter crankcase on compression stroke Varies the volume of ervoir of fuel for me-

power stroke. engine. throat. and trap fuel mixture in crankcase on fuel and air mixture to tering to carburetor

The carburetor starts its action and operates as follows:

PRESSURE IN CRANKCASE

VACUUM IN CRANKCASE

4. The carburetor throat is a Venturi tube, large at each end with a smaller center passage, When air rushes through this tube, the air pressure at the center is less.

5. By inserting a tube from the carburetor float bowl into this center area, the difference in air pressure will force fuel up through this tube, where it is picked up by, and mixed with, the air.

1. The crankshaft rotates when the starter rope is pulled (or electric starter motor engaged - electric start models).

2. The rotating crankshaft moves the piston up and down in the cylinder. This creates pressure and vacuum alternately in the crankcase.

3. The vacuum created by movement of the piston upward in the cylinder opens a reed valve - then air rushes through the throat of the carburetor.

PRESSURE AREA

4-29

"F" SER ENGINE F

FUEL SYSTEM COMPON 6. Turbulence around the throttle disc helps

to mix the fuel and air.

7. A s fuel and air mixture enters the crankcase through the reed valves, it is near a gaseous state. The engine, when cold, will not vaporize the mixture completely. As the engine warms up, the mixture is heated in the crankcase and becomes a consistently even gas.

ES (Cont.) UEL SYSTEM NTS AND THEIR FUNCTION

PRIMER OPERATION Examine the primer system. A pneumatic primer forces compressed air into the float bowl chamber which forces fuel into the carburetor venturi for cold engine starting.

PRIMER ACTIVATED

1/2 TURNSETTING

The float valve consists of a needle and seat assembly activated by a cork float in the float bowl. The needle rests on the float arm and is held in place by

Float

a spring clip. The needle is rubber-tipped so it will readily seal against the brass seat.

If the float bowl is empty, the cork float rests on the bottom of the bowl. As fuel enters the float bowl, the float rises, moving the needle into the seat, shutting off the fuel supply. As the engine uses fuel, the float drops slightly and the needle moves off the seat, maintaining a constant fuel supply to the engine.

PRIMER HOSE

CLIP

The carburetor is completely automatic. As fuel enters a single metered jet it is mixed with incoming air to from the correct combustible mixture. The amount of fuel flow through the metering jet is regulated by the altitude needle.

There are no adjustments to be made to regulate the amount of fuel entering the carburetor venturi. There is an atmospheric pressure adjustment that would have to be made if ' the engine is operating in very high o r very low altitudes.

All carburetors require a final adjustment of the altitude needle prior to putting the mower into service.

To adjust, proceed a s follows:

1. Pre-set altitude needle 1/2 turn from

2. Start engine and allow to run for 3 to 5 seat.

minutes to warm up. 4-30

“F” SERIES (Cont.) ENGINE FUEL SYSTEM

FUEL SYSTEM COMPONENTS AND THEIR FUNCTION

AIR ADJUSTMENT (CONTINUED) The governor will control the amount of air/fuel entering the engine. The

3. Place speed control lever in HIGH SPEED purpose of the atmospheric pressure running position (3100-3300 R.P.M.) Observe adjusting needle is to mix the right engine operation. If not running smoothly, turn amount of fuel with the correct altitude needle counterclockwise approximately amount of incoming air.

operation. at a time to Obtain proper engine 7. In the position no is the

4. Slowly turn altitude needle counterclockwise until engine is running smoothly. Allow engine to run for one or two minutes to make sure adjustment is not too lean.

5. Place speed control lever in LOW SPEED running position (2400-2600 R.P.M.) and check operation.

6. After carburetor adjustment is completed, shut off engine. IMMEDIATELY attempt to restart engine. DO NOT PRIME A HOT ENGINE. It should start

starting engine at both HIGH and LOW speed settings. If difficult to restart, turn altitude needle 1/8 turn counterclockwise to richen fuel mixture and obtain easy restarting.

within 2 pulls on starter handle. Check

FUEL TANK VENTING

carburetor vent passage. Therefore, the float bowl pressure has been eliminated and the fuel supply to the carburetor venturi is cut off, stopping the engine.

CLOSED SETTING

Fuel tanks must be vented to prevent vacuum forming and stopping flow of fuel. Tank caps will have a vent hole. A closed vent will create a vacuum in the tank as fuel is used - and eventually cause the engine to stop. In a few minutes the vacuum will decrease and the engine can be started again, but it will stop again in a short period of time, The vent hole can become clogged with dirt, Check vent hole before each operation and clean if necessary.

BAFFLE

"F" SERIES (Cont.)' ENGINE FUEL SYSTEM

FUEL SYSTEM COMPONENTS AND THEIR FUNCTION FUEL TANK VENTING (Cont.)

GASKET

I

SHUT-OFF VALVE The fuel tank screen assembly or the shut- off valve can become clogged. This can be checked easily by removing the fuel hose, opening the valve and observing for fuel flow through the valve. Replace the fuel shut-off assembly if damaged.

Shut-off valve is secured to fuel tank with a spring clip; exercise care when re-installing to fuel tank.

SAFETY WARNING

DO NOT SUBSTITUTE WITH IN- FERIOR FUEL HOSE WHICH MAY

TUNE DETERIORATION. LEAKAGE

SION AND/OR FIRE.

CAUSE LEAKAGE FROM PREMA-

OF FUEL MAY CAUSE AN EXPLO-

4-32 . . . . . . . . . . . . . . . . . . . . . . . . . . .

PRIMER HOSE

AIR VANE LINE

ADJUSTMENT NEEDLE \ FLOAT

The carburetor used on the early model F series engines is automatic. No fuel adjustments are necessary to regulate fuel intake. A single, metered jet allows the correct amount of fuel to mix with the incoming air which is regulated by a single adjusting needle. Adjustment must be changed when a significant change in altitude is encountered.

Two plastic plugs are available and recommended for installation in the screw holes located in the back wall of the air filter box. Dirt then is prevented from entering the air box. The part number is 611545.

. . . . . . . . . . SERVICE BULLETIN REFERENCES REVISED 1983

"F" SERIES (Cont.)

AIR FlLTER If engine is flooded, fuel can drain back into filter, As filter becomes saturated, incoming air picks up more fuel, causing greater flooding. A puckered filter will allow air and dirt to bypass filter. Make certain that filter covers cup area. If oiled properly, filter is very efficient. First wash out with fuel, o r solvent, blow dry with compressed air, then apply 10 to 15 drops of oil, Squeeze several times to distribute oil. If engine "smokes" for no apparent reason, filter may be saturated with fuel mix o r may need cleaning.

On later production models the air filter cover was retained with a clip or bail.

To remove grasp the cover, loosen snap and open cover.

NOTE

On early models the air filter element MUST BE installed so the small additional piece faces the venturi opening as illustrated. Also make sure it is positioned Squarely between both screw holes. If incorrectly installed, the corner of the secondary filter will be drawn into carburetor throat thereby restricting air flow, resulting in a rich fuel mixture entering the engine. Later production, this small square piece (filter) was eliminated.

A dirty air cleaner element will create a noticeable power loss, and may reduce engine life.

Operating engine without filter element, or filter element without sufficient oil will shorten engine life. Reinstall filter in the same position which it was removed to prevent imbedded particles in intake side from entering carburetor.

“F” SERIES (Cont.) “F” SERIES CARBURETOR IDENTIFICATION

F100 SERIES (EARLY MODELS) ADJUSTABLE ALTITUDE NEEDLE VALVE

VARIABLE SPEED

1 /2 TURN COUNTER- CLOCKWISE IF SPEED CONTROL LEVER IS IN

HIGH POSITION

1 /4 TURN COUNTER- CLOCKWISE IF SPEED CONTROL LEVER IS

IN LOW POSITION

F100 SERIES (LATER MODELS) ADJUSTABLE ALTITUDE NEEDLE

VARIABLE SPEED

1 /3 - 1 /2 TURN CLOCKWISE IF SPEED CONTROL LEVER IS IN

HIGH POSITION

F100 SERIES (LATER MODELS) ADJUSTABLE FUEL FLOW VALVE

VARIABLE SPEED

1 /3 - 1/2 TURN CLOCKWISE IF SPEED CONTROL LEVER IS IN

HIGH POSITION

TO INCREASE

SPEED

SPEED CONTROL

LEVER

FUEL FLOW VE

4-34

“F” SERIES (Cont.) F-SERIES CARBURETOR IDENTIFICATION

F300 SERIES ADJUSTABLE FLOW VALVE SINGLE SPEED

4-35

HIGH SPEED

The carburetor is completely automatic. As fuel enters a single metered jet it is mixed with incoming air to from the correct combustible mixture. The amount of fuel flow through the metering jet is regulated by the altitude needle.

There are no adjustments to be made to regulate the amount of fuel entering the carburetor venturi. There is an atmospheric pressure adjustment that would have to be made if the engine is operating in very high o r very low altitudes.



1. Pre-set altitude needle 1/2 turn from seat.


3. Place speed control lever in HIGH SPEED running position (3100-3300 R.P.M.) Observe engine operation. If not running smoothly, turn altitude needle counterclockwise approxi-

4-36 . . . . . . . . . . * . . . . . . . . . . . . . .

PASSAGES

mately 1/8 turn at a time to obtain proper engine operation.

4. Slowly turn altitude needle counterclockwise until engine is running smoothly. Allow engine to run for one or two minutes to make sure adjustment is not too lean.

5. Place speed control lever in LOW SPEED running position (2400-2600 R.P.M.) and check operation.

6. After carburetor adjustment is completed, shut off engine. IMMEDIATELY attempt t o restart engine. DO NOT

within 2 pulls on s tar ter handle. Check starting engine at both HIGH and LOW speed settings. If difficult to restart, turn altitude needle 1/8 turn counterclockwise to richen fuel mixture and obtain easy restarting.

PRIME A HOT ENGINE. It should start

The governor will control the amount of air/fuel entering the engine. The purpose of the atmospheric pressure adjusting needle’ is to mix the right amount of fuel with the correct amount of incoming air.

. . . . . . . . . . . . . . . SERVICE BULLETIN REFERENCES

PRIMER

Examine the primer system. A pneumatic primer forces compressed air into the float bowl chamber which forces fuel into the carburetor venturi.

place that part on assembly. NOTE

A leaking primer will cause hard starting and a surging operation.

4-37

“F” SERIES (Cont.) F-100-300 SERIES CARBURETOR

(WITH ADJUSTABLE FUEL FLOW NEEDLE VALVE

ADJUSTMENT PROCEDURES

1.

2.

3.

Always adjust the governor to operate engine between 3100-3300 R.P.M. before proceeding with carburetor adjustments.

NOTE All carburetors require a final adjustment of the needle valve prior’ to putting the mower into service.

VENTED CARBURETOR ADJUSTMENT

Turn needle valve slowly in a clockwise direction using a 1/4 inch open end wrench until it seats lightly.

NOTE

Do not force it against the seat as it can become damaged.

After seating, turn counterclockwise 2 full turns.

Start and run engine to warm it up to normal operating temperature. (3 to 5 minutes) With engine running in “normal” (approximately 3200 R.P.M.), slowly turn needle valve clockwise (turning the wrench to the left) approximately 1/8 turn at a time until it runs smooth and even. After the carburetor has been adjusted for smooth and even running, turn needle

4.

5.

valve counterclockwise (turning the wrench to the right) approximately 1/8-1/4 turn. This wil l correctly set the carburetor for easier starting and cold running. After each movement of needle valve, wait for the engine to respond to the adjustment.

Place speed control lever in LOW SPEED running position (2400-2600 R.P.M.). Observe engine operation. If not running smoothly, readjust needle slightly. Recheck high speed operation again.

After carburetor adjustment is completed, shut off engine. IMMEDIATELY attempt to restart engine. DO NOT PRIME A HOT ENGINE. It should start within 2 pulls on starter handle. Check starting engine at both HIGH and LOW speed settings. If difficult to restart, turn altitude needle 1/8 turn, counterclockwise to richen fuel mixture and obtain easy restarting.

4-38

“F” SERIES (Cont.) F100-300 SERIES CARBURETORS ADJUSTABLE FUEL FLOW NEEDLE VALVE

VENTED PRIMER

Examine the primer assembly. A vent hole is located in the primer bulb of this fuel system. When the bulb is depressed, the vent hole will close and forces air through the primer hose into the carburetor for priming which forces fuel up into the venturi.

When the bulb is released, air enters the primer bulb for the next stroke.

VENT HOLE OPEN

4-39

"F" SERIES (Cont.)

(PLASTIC BODY) F 1 00-F3OO SERIES CARBURETORS

MAINTENANCE-REPAIR AND ADJUSTMENTS-SERVICE FLOAT ADJUSTMENT

Float Setting

Remove float bowl and gasket. Invert carburetor. With float arm resting on float valve needle, the top of float should be 7/16-15/32 inch above edge of carburetor body a s shown. Obtain measurements at two points at right angles to each other.

If adjustment is required; using needle nose pliers bend float a rm as shown. DO NOT bend float arm by applying pressure 'to float, this will damage rubber t ip on inlet needle.

NOTE

Tightening hinge to pivot pin will prevent inlet needle from not seating correctly when mower crosses uneven terrain. This condition is

4-40 called "fluttering."

I I


Check pin clip on float arm by rotating carburetor sideways. If clip falls off float arm -- replace it.

ON NOZZLE

The Nozzle Filter will provide a secondary filtering device to minimize the possibility of "fuzz" o r other minute particles getting into the carburetor area, which causes engine stalling, including hard restarting after shut down.

We recommend the use of the Nozzle Filter in all carburetors. Make sure the nozzle is free from dirt and "fuzz" - then install filter on the nozzle. Hold float up and lift bowl carefully in place. (For easier installation, take carburetor off and turn upside down.)

"F" SERIES (Cont.) F1 00-F300 $ERIES CARBURETORS (PLASTIC BODY)

MAINTEANCE-REPAIR AND ADJUSTMENTS-SERVICE FLOAT AND VALVE ASSEMBLY HOSE

The float valve consists of a needle and seat assembly, activated by a float in the carburetor bowl. The steel needle is rubber tipped and the seat brass. This combination eliminates possible sticking and provides a perfect seal. The needle rests on float arm, held in place by a spring clip. Operation is automatic. When float bowl is empty, float rests on bottom of bowl. As fuel enters bowl of carburetor, float rises, moving needle valve into seat and shutting off fuel. As engine uses fuel, float drops slightly, allowing more fuel to enter bowl, maintaining a constant fuel level in bowl. Needle, seat and spring clip must be replaced as an assembly. They are matched to form a perfect seal. Remove float bowl and examine float appearance. Float should be glossy because of epoxy sealer. If dull in appearance, o r portions of epoxy have chipped away - replace float.

NOTE Do not clean float with any type of solvent or carburetor cleaner. Re- place it.

Some of the problems you may encounter with the float valve a re as follows:

Cause

VARNISH

SPRING WIRE CLIP COMES OFF NEEDLE AND SEAT NOT MATCHED FLOAT ARM NOT SET CORRECTLY

PIVOT PIN CORRODED OR BENT FLOAT STRIKING NOZZLE VARNISH OFF FLOAT

LOOSE FLOAT HINGE CLIP ON PIVOT PIN

Effect

Stops up openings


Fuel supply can't be shut off from float bowl Set too high - carburetor floods -Engine runs rich Set too low - carburetor starves - Engine runs lean

Float sticks

Float sticks Float soaks up fuel, changing floating characteristics

Engine 4 cycles excessively when bumped or jarred

Remedy

Clean out carburetor with solvent Replace clip

Replace needle and seat as an assembly Set correctly

Set correctly

Replace pin

Replace float Replace float

Crimp float hinge clip on pivot pin for tighter fit

“F” SERIES (Cont.) F1 00-F200-F300 SERIES REED VALVES

(ALL MODELS)

mum allowed clearance is .015 inch. Replace reeds if necessary.

4. Install reeds in crankcase cover, smooth edge down and with rough edge facing away from the carburetor mounting holes as shown.

REED VALVE SERVICING

1. Remove crankcase cover a s described in Chapter 7 - POWERHEAD.

2. Crankcase cover and reed valve assembly may be cleaned with same solvent used to clean carburetor. Exercise care in cleaning reeds, so a s not to distort them. Bent or distorted reeds must be replaced.

NOTE


3. Check for excessive clearance between reed tip and reed plate using automotive type feeler gauge as illustrated. Maxi-

Apply Screw-Loc (Loctite) OMC Part No. 384848 to threads of reed valve screws.

4-42

"F" SERIES (Cont.) F1 00-F300 FUEL SYSTEM TROUBLE SHOOTING

EARLY MODELS WITH ALTITUDE NEEDLE VALVE FUEL SYSTEM TROUBLE SHOOTING

1. Check for fuel in tank. off (Tank) valve should be open.

vent hole in gas cap. Make sure it is not

zzle in barrel of carburetor and push

visible. rom tank thru tank filter, valve

ose from tank valve. Turn valve if fuel is flowing from tank. If

so, restriction is in fuel hose. Wash out in solvent and blow with compressed air.


NOTE

This test does not apply to later model plastic carburetors with the adjustable fuel flow needle valve.


\

B. Depress primer bulb and place finger over end of hose. The bulb should remain collapsed. If not,

bulb and hose assembly.

close fuel valve and remove carburetor. Re- move float chamber.

arm is free.

4-43

"F" SERIES (Cont.)

CARB.-AIR-FILTER ASSEMBLY

GASKET RETAINER

PASSAGE

A I R FILTER ASSEMBLY AIR FILTER

If engine is flooded, fuel can drain back into filter. As filter becomes saturated, incoming air picks up more fuel, causing greater flooding. A puckered filter will allow air and dirt to bypass filter. Make certain that filter covers cup area. If oiled properly, filter is very efficient. First wash out with fuel, then apply 10 to 15 drops of oil. Squeeze several times to distribute oil. If engine "smokes" for no apparent reason, filter may be saturated with fuel mix or may need cleaning.

To remove grasp the cover, loosen snap and fold cover down.

4-56

NOTE

A dirty air cleaner element will create a noticeable power loss, and may reduce engine life.

NOTE

Operating engine without filter element, or filter element without sufficient oil will shorten engine life. Reinstall filter in the same position which it was removed to prevent imbedded particles in intake side from entering carburetor.

"F" SERIES (Cont.) F200 SERIES COMMERCIAL CARBURETOR

METAL BODY

1-1/2 TURNS SETTING

The carburetor is completely automatic. As fuel enters a single metered jet it is mixed with incoming air to form the correct combustible mixture. The amount of fuel flow through the metering jet is regulated by the altitude needle.

There are no adjustments to be made to regulate the amount of fuel entering the carburetor venturi. There is an atmospheric pressure adjustment that would have to be made if the engine is operating in very high o r very low altitudes.





3. Slowly turn altitude needle counterclockwise until engine is running smoothly. Allow engine to run for one or two minutes to make sure adjustment is not too lean.

4. If not running smoothly, turn altitude needle counterclockwise approximately 1/8 turn at a time to obtain proper engine operation.

5. After carburetor adjustment is completed, shut off engine. IMMEDIATELY attempt to restart engine. DO NOT PRIME A HOT ENGINE. It should start within 2 pulls on starter handle. Check starting engine at both HIGH and LOW speed settings. If difficult to restart, turn altitude needle 1/8 turn counterclockwise to richen fuel mixture and obtain easy restarting.

The governor will control the amount of air/fuel entering the engine. The purpose of the atmospheric pressure adjusting needle is to mix the right amount of fuel with the correct amount of incoming air.

“F” SERIES (Cont.) F200 SERIES COMMERCIAL CARBURETOR

METAL BODY

PRIMER OPERATION

Examine the primer system. A pneumatic primer forces compressed air into the float bowl chamber which forces fuel into the carburetor venturi for cold engine starting.

PRIMER ACTIVATED

4-58


METAL BODY FLOAT ADJUSTMENT

Float Setting

Remove float bowl and gasket. Invert Car- buretor. With float arm resting on float valve needle, the top of float should be 7/16-15/32 inch above edge of carburetor body as shown. Obtain measurements at two points at right angles to each other.

If adjustment is required; using needle nose pliers bend float arm as shown. DO NOT bend float arm by applying pressure to float, this will damage rubber tip on inlet needle.

Check hinge on float arm to be sure it is secured to pin. Use needle nose pliers and tighten hinge as shown.

NOTE

Tightening hinge to pivot pin will prevent inlet needle from not seating correctly when mower crosses uneven terrain. This condition is called "fluttering."

Operation is automatic, When float bowl is empty, float rests on bottom of bowl. As fuel enters bowl of carburetor, float rises, moving needle valve into seat and shutting off fuel. As engine uses fuel, float drops slightly, allowing more fuel to enter bowl, maintaining a constant fuel level in bowl.

4-59


METAL BODY

Needle, seat and spring clip must be replaced as an assembly. They are matched to form a perfect seal. Remove float bowl and examine float appearance. Float should be glossy because of epoxy sealer. If dull in appearance or portions of epoxy have chipped away - replace f loat.

NOTE Do not clean float with any type o f solvent or carburetor cleaner. Re- place it.

CLEANING AND MAINTENANCE

NOTE

Never run drill bits or other metal objects into or through passages. Damage will result.

Before blowing passages out, determine the direction that fuel and air normally flows and blow air in opposite direction.

NOTE

Always replace gaskets and other parts that may be questionable when reassembling.

FLOAT

SPEED NOZZLE

4-60

"F" SERIES (Cont.) F 2 0 0 FUEL SYSTEM TROUBLE SHOOTING

COMMERCIAL CARBURETOR METAL BODY

1. Check for fuel in tank.

2. Remove air filter element.

3. If spurting of fuel is not visible.


5. If fuel is not spurting from nozzle, when being primed, close fuel valve and remove carburetor. Re- move float chamber.

A. Fuel shut off (Tank) valve should be open.

B. Examine vent hole in gas cap. Make sure it is not restricted.

A. Watch nozzle in barrel of carburetor and push primer bulb down rapidly.

B. Fuel should spurt from top of nozzle.

A. Remove fuel line from carburetor to determine if fuel is flowing from tank thru tank filter, valve and hose.

B. If not, remove hose from tank valve. Turn valve on to determine if fuel is flowing from tank. If so, restriction is in fuel hose. Wash out in solvent and blow with compressed air.


B. Depress primer bulb and place finger over end of hose. The bulb should remain collapsed. If not, replace primer bulb and hose assembly.

C. If primer hose is disconnected, engine will run extremely rich (lost vacuum).

A. Check float valve and seat assembly.

B. Check float level adjustment.

C. Check to make sure movement of float and float arm is free.

D. Check the throttle valve and shaft for freedom of movement.

E. Check for dirt o r water in bowl o r passages.

F. Blow out altitude a i r vent passage.

4-61

D=400 SERIES GOVERNOR

GOVERNOR OPERATION

Some "D' 400 series engines are equipped with a variable governor, with operating speeds of 2500 RPM (LIGHT) up to 3200 RPM (NORMAL). This is done by moving the control lever. This movement of the variable governor control lever changes the tension on the governor spring which regulates the governed speed of the engine.

Those "D" 400 series engines without the variable governor control operate at a fixed speed of 3200 RPM. The governor adjustment for fixed speed engines is the same as variable speed engines.

GOVERNOR SERVICING

1. Remove spark plug and install piston stop, part no. 677389. Remove fuel and primer hoses from carburetor. Remove shroud mounting screws and remove shroud from engine.

2. Using a box end wrench, loosen and remove flywheel nut.

3. To loosen flywheel use a soft hammer. Strike top of thick flywheel fin while lifting on opposite side with your hand.

4. After removing flywheel, note position of flywheel key. Key must be installed with the straight edge in a vertical (straight up and down) position. It should not be installed with straight edge parallel to the crankshaft taper. Remove key with a pair of side cutters or dikes. Remove air baffle assembly.

MAKE SURE KEY IS INSTALLED CORRECTLY

RIGHT WRONG

SERVICE BULLETIN REFERENCES 5-1

D = 4 0 0 SERIES GOVERNOR Remove variable speed spring from governor lever and remove governor assembly. Examine governor spring. They are color coded for identification. Green 2500 RPM, yellow 3200 RPM, Red 2800 RPM, and Blue 4000 RPM. DO NOT interchange springs. If replacement is necessary, refer to parts book of engine being repaired.

NYLON T H R U S T COLLAR

WASHER T H R U S T

" . - GOVERNOR

YOKE

GOVERNOR WEIGHTS

GOVERNOR REASSEMBLY

GOVERNOR COLLAR

GOVERNOR

GOVERNOR S P R I N G

GREEN 2500 RPM YELLOW 3200 RPM RED 2800 RPM BLUE 4000 RPM

1. When reassembling the "D" 400 series governor notice that there is a groove around the outside diameter of the nylon thrust collar. The two lugs on the governor lever are inserted into this groove. Also, the groove in this thrust collar contains two webs. One of these webs must be placed within the lugs on the governor lever.

I THRUST

2. Slide the governor lever and thrust collar onto the crankshaft and hook the ends of the governor lever into the two slots on the dust cover.

5-2 SERVICE BULLETIN REFERENCES

D-400 SERIES GOVERNOR 3. Hook the variable speed spring into the

small hole on the governor lever.

4. Apply a light coat of Lawn-Boy “A” grease or equivalent to both sides of the hardened steel thrust washer and on the top of the governor collar. Position thrust washer on top of nylon thrust collar. Install governor spring, collar, weights and yoke. Prior to installing governor collar examine for “grooves” or excessive wear. Replace if necessary.

NOTE

The governor yoke has two”dimp1es” (see arrows). These dimples are used to drive the governor yoke. Install as shown.

G O V E R N O R A D J U S T M E N T

Special tool part #604541 should be used for checking the governor adjustment on “D” series engines. With the governor assembly in place slip the gauge onto the crankshaft and hold down

governor is properly adjusted there- should be approximately 1/8” 3/16” between the top of the I

governor rod and the bottom of the governor lever. To make any necessary adjustments simply bend SPECIAL TOOL the governor lever up or down with a pair of pliers to obtain the proper clearance.

. ~ ~ -

I 3‘/32” I

The governor lever is creased diagonally to simplify adjustment bend lever along crease.

I-____- ’LA SERVICE BULLETIN REFERENCES 5-3

REVISED 1978

D=40O SERIES GOVERNOR REASSEMBLY T'IPS

1. Check flywheel for wear or damage and strength of magnets.

2. Check flywheel keyway for distortion and/or cracks. Key must be installed with the straight edge in a vertical (straight up and down) position. It should not be installed with straight edge parallel to the crankshaft taper.

3. (EARLY D-400 SERIES ENGINES). On the inside of the flywheel next to the keyway there is a lug. This lug is part of the flywheel casting and helps drive the governor. Before installing a flywheel, rotate the governor assembly so one' of the longer sides of the governor yoke is next to the keyway in the crankshaft. Then the flywheel can be installed with the lug clearing the governor.

Flywheel hub and crankshaft taper must be absoluteIy clean void of grease and oil.

4. Flywheel nut should always be torqued properly when flywheel is re-installed. Correct torque is 30 foot pounds.


RIGHT WRONG

5 4 SERVICE BULLETIN REFERENCES

D-600 SERIES GOVERNOR GOVERNOR OPERATION

The governor on the D-600 series engine is serviced in the same manner as that on the D-400 series engine. Refer to page 5-1 for disassembly procedure. An important difference is in the governor thrust collar. The thrust collar at the left is the one used on the D-400 series engine and the one at the right is the new one used on the new D-600 ser ies engine. THEY ARE NOT IN- TERCHANGEABLE.

SAFETY WARNING

NEW 0600

SERIES

NON-INTERCHANGEABLE

THE D-600 SERIES ENGINE WILL RUN IN REVERSE IF THE OLD (D-400) GOVERNOR IS USED, I.E., I F P R E - I G N I T I O N OCCURRED, STARTING THE ENGINE IN RE- VERSE. THE NEW (D-600) THRUST COLLAR IS DESIGNED TO PRE-

to page 5-2. When reinstalling them, a light coat of Lawn-Boy “A’’ grease should be applied to top of governor thrust collar. Never stretch a governor spring; it controls the speed of your engine. Also, put a thin coat of Lawn-Boy “A” grease on both sides of thrust washer. Before reinstalling assem-

Here is an exploded view of governor assembly. bly; always check governor collar for wear and/or Reassembly is same as D-400 series engines. Refer burrs. Surging could result if it is damaged.

VENT T H I S BY IMMEDIATELY SHUTTING THE FUEL SUPPLY OFF.

D-600 SERIES GOVERNOR GOVERNOR ADJUSTMENT RIGHT

NOTE

Before making the adjustment, turn the variable speed knob to "light" position and rotate the governor thrust collar clockwise, as far as it will go.

G O V E R N O R T H R U S T C O L L A R ROTATED CLOCKWISE

Governor lever i s creased diagonally to simplify adjustment bend lever along crease.

5 6 .REVISED 1977 SERVICE BULLETIN REFERENCES

"F" SERIES (Cont.) F 1 0 0 SERIES G O V E R N O R

GOVERNOR ASSEMBLY AND OPERATION (EARLY MODELS BEFORE 1 98 1 ) (HEX SHAPED, GOVERNOR COLLAR)

The governor air vane assembly is an in- As mowing conditions change the governor tegral component of the carburetor. The air vane responds instantly to engine run- governor air vane (part of the throttle shaft) ning demands. The function of the governor extends through a "tunnel" in the shroud air vane is to control engine speed. An alti- mounting base. As the flywheel rotates an tude adjustment needle regulates the right air flow is created against the air vane amount of fuel with the correct amount of which opens or closes the throttle shaft. incoming air,

"F" SERIES (Cont.) F 1 0 0 SERIES GOVERNOR

REMOVING AIR VANE ASSEMBLY (EARLY MODELS) (HEX SHAPED GOVERNOR COLLAR) SAFETY WARNING

1. Remove two carburetor mounting screws USE CARE WHEN REMOVING CAR- and remove carburetor and air vane as- BURETOR AND AIR VANE ASSEM- sembly as shown. Special care MUST BE BLY FROM ENGINE. DAMAGE TO taken when removing carburetor to pre- AIR VANE WILL CREATE AN EN- vent damaging air vane assembly. GINE OVERSPEED CONDITION.

AIR BAFFLE REMOVED FOR CLARITY

2. Release governor spring tension by gently raising hex shaped governor adjusting collar until collar is above ribs on speed control lever. Rotate adjusting collar clockwise until two ends of governor spring are aligned. Lower adjusting collar back onto speed control lever.

3. Using needle nose pliers remove throttle disc from throttle shaft as shown. Note position of throttle disc so during reassembly disc is installed correctly. Ex- amine throttle disc for excessive wear.

4-45


(EARLY MODELS) (HEX SHAPED GOVERNOR COLLAR)

4. Lift air vane and throttle shaft slightly and unhook upper end of governor spring from air vane hub as shown. Remove air vane and throttle shaft.

8. Examine all components removed for damage o r wear and replace as required.

4-46

5. Carefully remove governor spring from governor adjusting collar.

6. Remove governor adjusting collar.

7. Using a wide bit screw driver, a s shown, GENTLY pry upwards on hub of speed control lever until speed control lever is free of retaining lug on carburetor. Remove speed control lever,

NOTE

USE CAUTION WHEN PRYING UP- WARDS ON THE LEVER TO PRE- VENT DAMAGING THE SPEED CONTROL LEVER.

CARBURETOR AIR VANE ASSEMBLY

CONTROL LEVER THROTTLE

DISC


REASSEMBLY GOVERNOR ASSEMBLY (EARLY MODELS) (HEX SHAPED GOVERNOR COLLAR)

1. Assemble speed control lever to carbu- 3. Insert straight end of governor spring into slot retor. The hub of the lever is retained of adjusting collar.

down when installing lever until hub "snaps" into position.

a lug or tab on the press 4. Insert air vane and throttle shaft into carburetor. Using needle nose pliers insert throttle disc into throttle shaft with flat edge of disc facing up, and small hole in disc facing air filter and two raised dimples in disc facing you. Rotate air vane and throttle shaft assembly. Assembly should move freely.

2. Install governor adjusting collar to speed control lever with spring slot facing you.

5. Preset governor spring tension by raising upward on governor adjusting collar as shown and rotate collar 1/2 turn (with speed control lever in HIGH SPEED position or 1/4 turn if speed control lever is in LOW SPEED position) COUNTERCLOCKWISE as illustrated. Lower adjustment collar onto speed control lever.

THE SPEED CONTROL LEVER CON- TAINS S P L I N E S . EACH SPLINE REPRESENTS 50-75 RPM. ROTAT- ING ADJUSTING COLLAR COUN- T E R C O L O C K W I S E INCREASES SPRING TENSION AND E N GIN E RPM. ROTATING ADJUSTING COL- LAR C L O C K W I S E DECREASES SPRING TENSION AND E N G I N E RPM.

4-47

“F” SERIES (Cont.) F 1 0 0 SERIES GOVERNOR (EARLY MODELS)

6. Insert air vane through slot in shroud mounting base and secure carburetor assembly to engine. Exercise care when inserting air vane assembly so not to damage the air vane.

---___- BAFFLE REMOVED FOR CLARITY

A SAFETY WARNING DO NOT SUBSTITUTE ELECTRIC START SHROUD BASE ON MANUAL

LOW GOVERNOR AIR VANE TO O V E R S P E E D ENGINE. ENGINE

CEEDS S A F E T Y CERTIFICATION FOR THROWN OBJECTS. ANY FOREIGN OBJECT STRUCK BY THE

OUS THROWN OBJECT THAT CAN CAUSE SERIOUS INJURY. ENGINE SPEED IN EXCESS OF 3300 R.P.M. WILL ALSO SHORTEN ENGINE LIFE. GOVERNOR ADJUSTMENT SHOULD NOT EXCEED 3300 R.P.M.

START MODELS. THIS MAY AL-

SPEED ABOVE 3300 R.P.M. EX-

BLADE CAN BECOME A DANGER-

I

GOVERNOR ADJUSTMENT

Engine speed (R.P.M.) is controlled by the governor spring tension. All mowers are run and tested at the factory, however, if the governor requires adjustment proceed as follows.

1. Grasp the hex shaped adjusting collar and gently raise collar upwards until collar is above splines on speed control lever as shown.

2. Rotate adjusting collar COUNTER- CLOCKWISE to increase spring tension ,increase engine R.P.M.). Rotating collar CLOCKWISE decreases spring tension (decreasing engine R.P.M.). Reinstall adjusting collar to speed control lever by pushing collar down in the locked position.

NOTE

Each spline on the speed control lever represents 50-75 R.P.M.

3. Use a tachometer to accurately measure engine R.P.M. Correct R.P.M. is 2400- 2600 LIGHT speed setting and 3100-3300 NORMAL setting.

4. Run engine and test for correct engine R.P.M. in both LIGHT and NORMAL settings. Adjust governor spring tension as required until engine R.P.M. is within specified range.

4-48

"F" SERIES (Cont. ) F 1 0 0 SERIES GOVERNOR

GOVERNOR ASSEMBLY AND OPERATION (ROUND GOVERNOR COLLAR)

The governor air vane assembly is an in- As mowing conditions change the governor tegral component of the carburetor. The air vane responds instantly to engine run- governor air vane (part of the throttle shaft) ning demands. The function of the governor extends through a “tunnel" in the shroud air vane is to control engine speed. An alti- mounting base. As the flywheel rotates an tude adjustment needle regulates the right air flow is created against the air vane amount of fuel with the correct amount of which opens or closes the throttle shaft. incoming air.

"F" SERIES (Cont.) F 1 0 0 SERIES G O V E R N O R (DISASSEMBLY)

REMOVING AIR VANE ASSEMBLY (ROUND GOVERNOR COLLAR) 1. Remove two carburetor mounting screws USE CARE WHEN REMOVING CAR-

and remove carburetor and air vane as- BURETOR AND AIR VANE ASSEM- sembly as shown. Special care MUST BE BLY FROM ENGINE. DAMAGE TO taken when removing carburetor to pre- AIR VANE WILL CREATE AN EN- vent damaging air vane assembly. GINE OVERSPEED CONDITION.

SAFETY WARNING

AIR BAFFLE REMOVED FOR CLARITY

I

2. To release governor spring tension, rotate adjusting collar counterclockwise until two ends of governor spring are aligned.

3. Using needle nose pliers remove throttle disc from throttle shaft as shown. Note position of throttle disc so during reassembly disc is installed correctly. Ex- amine throttle disc for excessive wear.

.____- ==LE REMOVED FOR CLARITY

ROUND COLLAR

4-50

(ROUND GOVERNOR COLLAR)

4.

5.

6.

7.

8.

Slide (lift) the complete governor assembly from the carburetor body.

NOTE

Do not damage or distort the governor spring during this disassembly.

Carefully remove governor spring from gover- nor adjusting collar.

Remove governor adjusting collar from the hub of air vane.

To remove or replace the speed control lever, it is necessary to first remove retainer from the carburetor body. Carefully pry it out of the holes without damaging it or the carburetor body.

Examine all components removed for damage or wear and replace as required.

SPEED

LEVER

SPEED CONTROL LEVER RETAINER

CARBURETOR ASSEMBLY

"F" SERIES (Cont.) F 1 0 0 SERIES G O V E R N O R

(ASSEMBLY ) REASSEMBLY GOVERNOR ASSEMBLY F100 SERIES (ROUND GOVERNOR COLLAR)

1. Reassemble speed control lever and retainer to carburetor if it was removed.

2. Insert long end of governor spring into square hole of speed control lever.

4. Assemble air vane and throttle shaft into carburetor with the air vane facing towards the front and coming to rest on top of ratchet ring of governor collar.

NOTE

Do not force the ratchet ring into the governor hub.

3. Assemble speed control collar onto governor 5. Place your finger on top of hub to hold it spring with the short end of spring inserted into stationary. small square hole under flange of collar.

6. Push the ratchet ring in slightly to permit it to slide into the hub and the lower end of throttle shaft to enter the pivot hole in carburetor body.

4-52


THROTTLE SHAFT AND DISC VALVE INSTALLATION (ROUND GOVERNOR COLLAR)

1. Insert throttle shaft into carburetor body with the notch in the air vane hub facing you. Gently attach governor spring to air vane hub.

2. Using needle nose pliers insert throttle disc into throttle shaft. Flat edge on throttle disc must be installed upwards facing. the air vane as shown. The small hole in the throttle disc must be installed facing the front of the carburetor as shown. Insert throttle disc until two half moon slots are touching throttle shaft as shown.

3. Rotate air vane and check movement of throttle disc. Check for binding and/or wear in carburetor throat.

GOVERNOR ADJUSTMENT

NOTE

Always use a tachometer to accurately measure engine R.P.M. Correct R.P.M. is 2400-2600 LIGHT speed setting and 3100- 3300 NORMAL setting.


2. Remove the throttle disc screw and disc. 5. Inspect all parts for wear or damage. Replace parts if necessary.

AIR VANE COLLAR

4-62

"F" SERIES (Cont.) F200 SERIES GOVERNOR COMMERCIAL CARBURETOR

GOVERNOR REASSEMBLY 3. Slide the assembly into the carburetor.

1. pre-assemble governor spring onto the air vane and throttle shaft with the hook end at the top.

4. Squeeze the clamp to open and slide it down onto the hub of carburetor.

2. Slide the clamp onto the shaft. Place the straight end of governor spring in slot of clamp.

NOTE

Do not apply tension to governor spring.

4-63

“F” SERIES (Cont.) F200 SERIES GOVERNOR COMMERCIAL CARBURETOR

5. Note the hole located in one side of throttle 7. Tighten the screw to 3-5 inch lbs. Move air vane disc. Always assemble the disc with the hole lo- and throttle shaft to check freedom of move- cated on the left side of the barrel as you face ment. If interference is noted, loosen and repo- the back of the carburetor. sition the disc.

8. To pre-set the governor spring tension, slide the clamp counterclockwise approximately 1/3 turn.

6. Place the disc on the flat surface of the throttle shaft and ’assemble the screw.

9. The final adjustment of the governor is made when running the engine.

NOTE

Adjust governor to run engine 3100-3300 R.P.M.

4-64

"F" SERIES (Cont.) F300 SERIES GOVERNOR

(SINGLE SPEED) (ASSEMBLY )

REASSEMBLING GOVERNOR ASSEMBLY F300 SERIES (ROUND GOVERNOR COLLAR)

1. Insert long end of governor spring into square hole located in rib of carburetor body.

2. Assemble speed control collar onto governor spring with the short end of spring inserted into small square hole under flange of collar.

SPRING IN HOLE

3. Assemble air vane and throttle shaft into carburetor with the air vane facing towards the front and ,coming to rest on top of ratchet ring of governor collar.

NOTE

Do not force the ratchet ring into the governor hub.

4. Place your finger on top of hub to hold it stationary.

5. Push the ratchet ring in slightly to permit it to slide into the hub and the lower end of throttle shaft to enter the pivot hole in carburetor body.

4-54

"F" SERIES (Cont.) F300 SERIES GOVERNOR

(ROUND GOVERNOR COLLAR) (ASSEMBLY - CON'T.)

THROTTLE SHAFT AND DISC VALVE INSTALLATION

1. Insert throttle shaft into carburetor body with the notch in the air vane hub facing you. Gently attach governor spring to air vane hub.

2. Using needle nose pliers insert throttle disc into throttle shaft. Flat edge on throttle disc must be installed upwards facing the air vane as shown. The small hole in the throttle disc must be installed facing the front of the carburetor as shown. Insert throttle disc until two half moon slots are touching throttle shaft as shown.

3. Rotate air vane and check movement of throttle disc. Check for binding and/or wear in carburetor throat.

PRESETTING AND ADJUSTING GOVERNOR

Preset governor spring tension by adjusting collar as shown and rotating collar 1/3 turn CLOCK- WISE as illustrated.

Engine speed (R.P.M.) is controlled by the gover- nor spring tension. All mowers are run and tested at the factory, however, if the governor requires adjustment proceed as follows:

1. Rotate adjusting collar CLOCKWISE to increase spring tension (increase engine R.P.M.). Rotating collar COUNTERCLOCKWISE decreases spring tension (decreasing engine R.P.M.)

NOTE

INCREASE

NOTE

Each click on the speed control collar Always use a tachometer to accurately represents approximately 50-75 R.P.M. measure engine R.P.M. Correct R.P.M. is

3100-3300 NORMAL setting.


PRINCIPLES OF M A G N E T O O P E R A T I O N D - 4 0 0 SERIES The two questions most commonly asked about a magneto a r e first, exactly what does it do in the engine, and second, just how' does it do it. The magneto is solely for IGNI- TION. It provide8 a current of sufficiently high voltage (up to 17,000 volts in a Lawn-Boy engine) to cause a spark to jump the gap between the spark plug electrodes and ignite the compressed fuel vapor at exactly the moment when the piston reaches near the top of the compression stroke. And how does it accomplish this? Following the complete cycle of the production of a spark at the plug is about the simplest way to explain it.

COIL PRIMARY

A N D S E C O N D A R Y

I CONDENSER

PERMANENT MAGNETS (cast into the flywheel) revolve around the rest of the magne- to as the flywheel rotates. Magnetic flux around the magnets passes through the coil winding in the PRIMARY COIL. This will induce a flow of current through the primary coil. The crankshaft also is rotating as the flywheel rotates. A CAM on the crankshaft opens and closes BREAKER POINTS. These breaker points, when closed, completes the circuit of the primary coil. When the cam opens these breaker points, the circuit of the primary coil is broken and the current ceases to flow. A CONDEN- SER connected across the points prevents arcing and burning of the points. The condenser also absorbs (drains) current remaining in the primary circuit. A SEC- ONDARY COIL is wrapped around the primary coil. The rapidly collapsing current in the primary coil induces a flow of current in the secondary coil of extremely high voltage. The more rapid the collapse, the higher the voltage. The secondary coil is connected directly to the SPARK PLUG through the HIGH TENSION LEAD. It is the current with high voltage from the secondary coilwhich jumps the gap between the

CAM BREAKER spark plug electrodes, caus- POINTS ing the spark which ignites

the fuel vapor in the combustion chamber. In a one-cylinder engine, this cycle is completed once for every rotation of the crankshaft,

SERVICE BULLETIN REFERENCES 6 1

I G N I T I O N W I R I N G D I A G R A M S - D - 4 0 0 SERIES HIGH TENSION

LEAD

SPARK CONDENSER GROUND PLUG

P R I M A R Y C I R C U I T POINTS CLOSED

PRIMARY CIRCUIT Current flow in the primary circuit is ob- The circuit is completed through the closed tained from the flow of magnetic flux lines breaker points and grounding. through the lamination assembly as the magnet sweeps past the .ends (heels) of the coil laminations.

POINTS OPEN

S E C O N D A R Y C I R C U I T SECONDARY CIRCUIT The secondary coil is wound around the primary coil.

When the breaker points open, the current in the primary coil collapses. The collapsing magnetic field induces a flow of current through the secondary coil.

The current in the secondary coil is sufficient to jump the gap between the spark plug electrodes, causing the spark which ignites the compressed fuel mixture in the cylinder.

The secondary current is then dissipated through grounding at the magneto and grounding at the plug.

THIS COMPLETE CYCLE OCCURS ONCE EVERY TIME THE FLYWHEEL ROTATES AROUND THE MAGNETO, OR ABOUT 3,000

GINE.

KNOWING THE PART EACH COMPONENT PLAYS IN PRODUCING IGNITION, IT'S

TIMES A MINUTE IN THE LAWN-BOY EN-

6-2

EASY TO SEE WHY IT IS NECESSARY TO HAVE: 1.

2.

3.

4.

CLEAN POINTS dirty, pitted or corroded points will retard the flow of current in the primary coil because they make a poor electrical connection.

PROPERLY ADJUSTED POINTS improperly adjusted points do not permit them to open at the right instant to inter- rupt the current at its peak. When you adjust the breaker point gap, you are "timing" the engine.

GOOD CONDENSER a weak condenser can cause arcing across the breaker points and will not permit a rapid enough collapse of the flux in the primary coil to induce enough voltage in the secondary coil for a good spark.

CLEAN AND PROPERLY GAPPED SPARK PLUG a dirty or improperly gapped plug cannot provide a good spark for ignition.

SERVICE BULLETIN REFERENCES

D-400 SERIES I G N I T I O N S Y S T E M

“D” 400 series engines have a twin spark ignition system. This system provides two different spark timings, one for starting and one for running. For starting, the spark-advance flyweight holds the cam in a position so that the igniting spark occurs at 6" of crankshaft rotation before the piston reaches the top of its upward travel. When the engine reaches approximately 1000 RPM, centrifugal force moves the flyweight out, rotating the cam to a position so that the igniting spark now occurs at 26" of crankshaft rotation before the piston reaches the top of its upward travel.

Push small end of spark, advance flyweight toward crankshaft. Hold tension of spring against crankshaft and return flyweight to original position. Allow smaller end of flyweight to drop down. Remove pin and spring.

Note: In reassembly, make sure the smaller end of the flyweight is on the keyway side of the crankshaft.

The assembly of the spark advance is correct when the small hair pin is horizontal to the flyweight and the spring loaded rod moves freely.

BREAKER POINT ADJUSTMENT

To check o r adjust point gap, place spark advance cam only. on crankshaft. Check and adjust points as described. See Breaker Point Adjustment on page 6-5.

MAGNETO ADJUSTMENTS


D-400 SERIES IGNITION SYSTEM COIL HEEL ADJUSTMENT The air gap between the coil heels and the flywheel magnets is .010 inch. To check this gap or to reinstall a coil insert a strip of .010 inch non-metallic shim stock between the coil heels and the flywheel magnets.

Use Lawn-Boy Air Gap Gauge Part No. 604659.

IGNITION PROBLEMS -_.-

Bad spark plug Burned o r pitted breaker points Terminal missing from spark plug (high Worn breaker point fiber rubbing block

Lead wire pulled out of coil Frayed insulation on wires Cracked insulation on lead wire Weak flywheel magnets Poor condenser or coil Spark advance assembly damaged o r

tension lead) cover Poor connections

installed incorrectly

BREAKER POINT SPRING, TERMINALS ASSEMBLY SEQUENCE The correct assembly sequence on the condenser terminal is breaker arm spring next to condenser body, then the 2 terminal connectors secured by a nut. See illustration. Correct assembly provides the proper tension (pressure) on the breaker arm wear block and breaker cam. If the breaker arm spring is reassembled next to the nut or between terminals excessive pressure is ap-

BREAKER ARM SPRING N U T

CONDENSER plied to wear block resulting in incorrect point gap.

SHUT-OFF GROUND WIRE When trouble shooting magneto problems make sure the shut-off ground wire terminals DO NOT touch the armature plate. If this happens, the electrical system will be permanently grounded. Also, the shut-off, switch may become inoperative if dirt and grime collects between the shut-off switch screw and the shut-off blade. Insulation on ground wire should also be examined.

ASSEMBLY TIPS

When inserting the high tension lead wire, coat the end of the insulated portion with OMC Adhesive "M" Part No. 318535 for a water-proof connection. - Twist lead wire into threaded coil casing as far as it will go. On early models only, bend clamp to secure high tension lead to coil.

6 4 REVISED 1978 SERVICE BULLETIN REFERENCES

MAGNETO ADJUSTMENTS.

B R E A K E R P O I N T A D J U S T M E N T D-400 SERIES To check point gap .020, rotate crankshaft until wear block is centered on lobe of cam;- MOVE' CRANKSHAFT TOWARD CARBURE- TOR AND HOLD IN THAT POSITION. Loosen breaker base screw, and place- gauge between points. Pivot breaker base until gap is correct. Retighten breaker base screw and recheck gap to make sure breaker base has not shifted. Check breaker points every 40-50 hours for wear or pitted condition. Replace as required.

NOTE

When setting the breaker points, the top of the crankshaft should be held toward the carburetor to eliminate the effect of tolerance accumulations and wear. Remember, the feeler gauge must be clean. After correct setting, the breaker base screw must be secured tightly.

CONDENSER

It is not necessary to replace a condenser every time the breaker points are replaced. Usually, the risk of condenser failure decreases as the condenser is used, and most condensers will last the life of the engine. However, if the condenser is thought to be the cause of an ignition problem, it must be checked for capacity, shortage o r leakage and resistance.

The condenser should be heated to approximately 100 DEG. F. before testing. This will eliminate the possibility of the condenser checking okay when cold, but failing under normal operating conditions. For example, a leak will show up much better at high temperatures.

NOTE

Do Not Over Heat. The expansion may crack some of the insulation. A simple method of heating a condenser is holding i t in your hand for a few minutes or placing it in an oven with a thermometer control.

The condenser clamp is the ground connection for the condenser and therefore, must be secured tightly.

BURNED OR PITTED BREAKER POINTS Always replace badly burned or pitted points. Do not file points.

WORN BREAKER POINT FIBER WEAR BLOCK Sometimes the fiber wear block which contacts the cam can wear down enough so that the breaker arm is shorted through the crankshaft. If this has hap- pened, replace the breaker points. On later model Lawn-Boy engines, part of the breaker arm has been cut away to minimize the possibility of shorting.

POOR CONNECTIONS Check wires for good connections, especially at condenser.

E

B R E A K E R POINT ARM


i

COIL of sharp blue color and should jump at least The magneto coil is seldom the cause of 1/4-3/8 inches to ground consistently. This ignition trouble. Therefore, other possible method of coil checking is not fool-proof and causes should be checked thoroughly before therefore, an approved coil tester is rec- the coil is examined. A simple method of ommended in many cases. With this equip- testing the coil is by checking the spark gap ment a primary and secondary continuity on the spark plug o r through the use of a check can be made a s well as coil output spark plug tester. Ignition spark must be and polarity.

IGNITION TESTING EQUIPMENT

IGNITION TESTING

Every servicing dealer should have a test unit on hand for checking coils and condensers. There are several good makes' on the market.

The following test data covers only coils and condensers. The Lawn-Boy Capacitor Dis- charge (solid-state) Module cannot be checked with conventional test equipment. Voltage applied to it will most likely result in damage. Therefore, the best way to check it is to use a standard test spark plug and observe for sufficient spark, or compare it to a CD Module which is known to be good.

TEST SPARK PLUG

A simple but effective means for checking ignition spark may be obtained using Spe- cial Tool Par t No. 426814.


SPARK PLUG 01400 AND D-600 SERIES There are many different types of spark plugs intended for various applications and therefore, it is extremely important that the correct plug be used in an engine and torqued correctly. Correct torque is 12 to 15 f t lbs.

LAWN-BOY recommends the use of the Champion CJ-14 spark plug because of its ability to supply, continuously, a hot spark for uninterrupted combustion. Plugs should be cleaned and gapped every 25 hours of operation.

NOTE Prior to installing a new plug always check plug gap. Plug gap is no longer pre-set at factory.

The correct gap for LAWN-BOY engines is:.

D-400 SERIES .025" D-600 SERIES .035"

DO NOT CLEAN PLUG IN SAND BLASTER.

SPARK PLUG ANALYSIS Normal

Few combustion deposits present on plug. Electrodes not burned o r eroded. Insulator tip color, brown to light tan. Insulator dry providing engine was not excessively choked prior to plug removal. ANALYSIS: Ignition and carburetor in good condition. Plug is correct heat range clean and replace, or install new Champions of same heat range.

Oxide Fouling

Electrodes not worn (may be covered with deposits). Insulator nose choked, splattered, o r "peppered" with ash-like deposits. In extreme cases, deposits are thrown against and adhere to the side electrode. Flying deposits may also wedge between the electrodes momentarily or permanently shorting out the plug.

ANALYSIS: Excessive combustion chamber deposits. Clogged exhaust ports or muffler.


D-600 SERIES SOLID STATE I G N I T I O N

HOW SOLID STATE I G N I T I O N WORKS

Solid state is a broad term applied to any engine’s ignition system which uses electronic devices such as diodes, transistors, silicon controlled rectifiers or other semi- conductors in place of one or more standard ignition components.

Electronic components are extremely small, have no moving parts, require no mechanical adjustments, are not subjected to wear, as with mechanical devices, deliver uniform performance throughout component life and under adverse operating conditions, and can be hermetically sealed, thus unaffected by dust, dirt, oil or moisture.

The C-D (Capacitor Discharge) system is breakerless, with an electronic component replacing the mechanical points and related accessories (breaker cam, spark advance assy., etc.). The flywheel contains permanent magnets, but there a r e no other moving mechanical parts.

Main difference between solid state and conventional ignition is the substitution of electronic components and circuitry for mechanical devices.

This is the solid state pack. It replaces conventional breaker points, condenser, coil, breaker cam and spark advance assembly.

The C-D (Capacitor Discharge) module can be tested very simply by using Lawn-Boy test spark

plug #426814, to see if it is producing a spark. If it is not, fault may be with switch, switch lead, flywheel, or air gap may be incorrect. Outside of these considerations there is no trouble shooting necessary. Again, only trouble shooting procedure for C-D (Capacitor Discharge) module is to check to see if it is producing a good spark. When making this check be sure the ON-OFF switch is in the “ON” position. If no spark is visible, disconnect the switch lead from the switch and again check for spark. No spark indicates a defective C-D (Capaci- tor Discharge) module, if a spark is present it indi- ca& a defective switch.

NOTE

The ignition switch is most vulner- able part of ignition system. Solid state module is dust and moisture proof. Ignition switch can be affected by moisture. It is definitely not advisable to clean engine with a pressurized water hose.


D-600 SERIES (cont’d)

SWITCH L E A D

MAGNET As flywheel magnets pass solid state module laminations, a low voltage alternating current is induced into charge coil.

CHARGE COIL

RECTIFIER

CAPACITOR

SPARK COIL

SPARK PLUG

I I I

TRIGGER COIL

SWITCH L E A D

MAGNET This alternating current passes through a rectifier, transforming it into direct current. Current is then stored in capacitor.

HARGE COIL

RECTIFIER

CAPACITOR

SPARK COIL

SPARK PLUG

I TRIGGER COIL

0-600 SERIES (cont'd)

Flywheel magnets rotate approximately 350" until they pass laminations, inducing a small electrical charge into trigger coil. At starting speeds, this charge has proper magnitude to turn on silicon controlled rectifier (solid state switch) at retarded position for easy starting. This is illustrated as 5" or retard firing position,


0-600 SERIES (cont'd)

When engine reaches approximately 800 evolutions per minute,. advance firing

commences. Flywheel magnets travel approximately 330°, at which time enough voltage is induced into trigger coil to fire silicon controlled rectifier (solid state switch). See advanced firing position 25'.

FLYWHEEL

SWITCH LEAD

When silicon controlled rectifier is trig- gered, up to 300 volts stored in capacitor travel to spark coil where it is stepped up instantaneously to a maximum of 30,000 volts and discharged across electrodes of

[=] MAGNET

CHARGE COIL spark plug.

RECTIFIER

CAPACITOR

SPARK COIL

SPARK PLUG

TRIGGER COIL


3. Insert non-metallic gauge between C-D pack laminations and magnets (magnets will pull the C-D pack in tightly). Two screws securing module a r e then tightened. The .OlO gap is set between two inside legs of laminations and magnets. Outer ends of laminations will be further from the flywheel since curvature of laminations does not conform to that of flywheel.

1. Flywheel and solid state module pack can be exposed very easily by removing shroud, fuel hoses and air baffle from armature plate. Remove kill switch lead from ignition switch.

2. Clearance is obtained by rotating the flywheel until flywheel magnets are adjacent to the solid state pack as illustrated. CORRECT AIR GAP IS .010.

NOTE


C.D. IGNITION PACK

& ONLY THESE 2 SURFACES (HEELS) BETWEEN FLYWHEEL MAGNET

OF C.D. LAMINATION ASSEMBLY.

FLYWHEEL

COUNTERWEIGHT

FLY WHEEL REPLACEMENT

1. Remove spark plug and install Piston Stop Part No. 677389.. Remove shroud, fuel hoses and air baffle from armature piate.

SAFETY WARNING

If engine has been running allow 10 seconds, before removing spark plug lead wire. This will allow charge in C-D pack to lead off.

Using a box end wrench remove flywheel nut. If necessary, use a soft headed (leather or plastic) hammer to loosen nut.

3. Place fingers under flywheel screen and apply upward pressure. At the same time, strike opposite side of flywheel at screen retaining screw with a soft headed hammer to break flywheel loose as shown.


RIGHT WRONG

0-600 FLYWHEEL IS USED ON SOME BUT NOT ALL D-400 SERIES ENGINES. CHECK PARTS LISTS CAREFULLY.

4. Remove flywheel. After removing flywheel, note position of flywheel key. Key must be installed with the straight edge in a vertical (straight up and down) position. It should not be installed with straight edge parallel to the crankshaft taper. Remove key with a pair of side cutters or dikes.

5. Check flywheel for wear and strength of flywheel magnets. Check keyway for distortion and/or cracks.

6. Flywheel nut should always be torqued properly when flywheel is re-installed. Correct torque is 30 foot pounds. Fly- wheel hub and crankshaft taper must be absolutely clean void of grease and oil.


C-D PACKS D-600 SERIES

PART NO. 681542 MANUAL START

F-SERIES

F SERIES C-D PACK

CLOSED TO RUN TYPE SYSTEM USED ON 1978 THRU 1982 MODELS.

These “F” Series C-D modules are not interchangeable with D-600 Series C-D modules.

PART NO. 681 544 ELECTRIC START SELF CHARGING

PART NO. 683215 GRAY

USED ON 1983 AND LATER COMPLIANT LAWN MOWERS.

I PART NO. 681546 ELECTRIC START

OPEN TO RUN TYPE SYSTEM USED ON ALL COMPLIANT MOWERS.

SPARK PLUG 01400 AND D-600 SERIES There are many different types of spark plugs intended for various applications and therefore, it is extremely important that the correct plug be used in an engine and torqued correctly. Correct torque is 12 to 15 f t lbs.

LAWN-BOY recommends the use of the Champion CJ-14 spark plug because of its ability to supply, continuously, a hot spark for uninterrupted combustion. Plugs should be cleaned and gapped every 25 hours of operation.

NOTE Prior to installing a new plug always check plug gap. Plug gap is no longer pre-set at factory.

The correct gap for LAWN-BOY engines is:.

D-400 SERIES .025" D-600 SERIES .035"

DO NOT CLEAN PLUG IN SAND BLASTER.

SPARK PLUG ANALYSIS Normal

Few combustion deposits present on plug. Electrodes not burned o r eroded. Insulator tip color, brown to light tan. Insulator dry providing engine was not excessively choked prior to plug removal. ANALYSIS: Ignition and carburetor in good condition. Plug is correct heat range clean and replace, or install new Champions of same heat range.

Oxide Fouling

Electrodes not worn (may be covered with deposits). Insulator nose choked, splattered, o r "peppered" with ash-like deposits. In extreme cases, deposits are thrown against and adhere to the side electrode. Flying deposits may also wedge between the electrodes momentarily or permanently shorting out the plug.

ANALYSIS: Excessive combustion chamber deposits. Clogged exhaust ports or muffler.


“F” SERIES SOLID STATE IGNITION

Recommended spark plug is Champion CJ-14. Spark plug gap is .035. Tighten to 12-15 ft. lbs.

HOW SOLID STATE IGNITION WORKS

Solid state is a broad term applied to any engine’s ignition system which uses electronic devices such as diodes, transistors, silicon controlled rectifiers or other semi- conductors in place of one or more standard ignition components.

Electronic components are extremely small, have no moving parts, require nomechanical adjustments, are not subjected to wear, as with mechanical devices, deliver uniform performance throughout component life and under adverse operating conditions, and can be hermetically sealed, thus unaffected by dust, dirt, oil or moisture.

The C-D (Capacitor Discharge) system is breakerless, with an electronic component replacing the mechanical points and related accessories (breaker cam, spark advance assy., etc.). The flywheel contains permanent magnets, but there are no other moving mechanical parts.

Main difference between solid state and conventional ignition is the substitution of electronic components and circuitry for mechanical devices.

This is the solid state pack. It replaces conventional breaker points, condenser, coil, breaker cam and spark advance assembly.

The C-D (Capacitor Discharge) module can be tested very simply by using Lam-Boy test spark plug #426814, to see if it is producing a spark. If it

is not, fault may be with switch, switch lead, flywheel, or air gap may be incorrect. Outside of these considerations there is no trouble shooting necessary. Again, only trouble shooting procedure for C-D (Capacitor Discharge) module is to check to see if it is producing a good spark. When making this check be sure the ON-OFF switch is in the “ON” position. Pull the starter rope, if no spark is visible, disconnect the switch lead from the C.D. pack, connect jumper wire from C.D. pack terminal to ground, and again check for spark. No spark indicates a defective C-D (Capacitor Discharge) module, if a spark is present it indicates a defective switch.

NOTE

The ignition switch is most vulner- able part of ignition system. Solid state module is dust and moisture proof. Ignition switch can be affected by moisture. It is definitely not advisable to clean engine with a pressurized water hose.

SERVICE BULLETIN REFERENCES REVISED 1978 6-7

"F" SERIES (Cont.)

MAGNET

CHARGE COIL RECTIFIER

CAPACITOR

As flywheel magnets pass solid state module laminations, a low voltage alternating current i s induced into charge coil.

A I SPARK COIL

I IGNITION SWITCH I

This alternating current passes through a recifier, transforming it into direct cur-

[*] MAGNET rent. Current i s then stored in capacitor.

RECTIFIER

CAPACITOR

SPARK COIL

SPARK PLUG

IGNITION SWITCH



POLE SHOE RTING LEG

ROTATION

CRANKSHAFT AT 5’ BTDC

Flywheel magnets rotate approximately 355’ until they pass laminations, inducing a small electrical charge into trigger coil. At starting speeds, this charge has proper magnitude to turn on the silicon controlled rectifier (solid state switch) at retarded position for easy starting. This is illustrated a s 5” 6’ retard firing position.



When engine reaches approximately 800 revolutions per minute, advance firing commences. Fly- wheel magnets travel approximately 335° at which time enough voltage is induced to trigger coil to fire the silicon controlled rectifier (solid state switch). See advanced firing position 24°-27°

UNNlNG LEG 5” ADVANCE

FLYWHEEL ROTATION

CRANKSHAFT AT 25” BTDC

MAGNET

When the silicon controlled rectifier is trig- gered, up to 300 volts stored in capacitor travel to spark coil where it i s stepped up instantaneously to a maximum of 30,000 volts and discharged across electrodes of spark plug.

CHARGE COIL

RECTIFIER

I SPARK COIL

SPARK PLUG

I IGNITION SWITCH

6-10 REVISED 1978. SERVICE BULLETIN REFERENCES


3 . Insert non-metallic gauge between C-D pack laminations and magnets (magnets will pull the C-D pack in tightly). Two screws securing module a r e then tightened. The .010 gap is se t between two square legs of laminations and magnets. The charging leg of the lamination will be further from the flywheel since curvature of laminations does not conform to that of flywheel.

9 5 1 1 9

1. Flywheel and solid state module pack can be exposed very easily by removing shroud, fuel hoses and air baffle from shroud base. Remove kill switch lead from ignition switch.

2. Clearance is obtained by rotating the flywheel until flywheel magnets are adjacent to the solid state pack as illustrated. CORRECT AIR GAP IS .010.

: NOTE


FLYWHEEL REPLACEMENT

1. Remove spark plug and install Piston Stop Part No. 677389. Remove shroud, fuel hoses and air baffle from shroud base.

2. Using a socket wrench, remove flywheel nut. Remove flywheel screen.


"F" SERIES (Cont.)

3. Place fingers under flywheel screen and apply upward pressure. At the same time, strike wide fin of flywheel with a soft headed hammer to break flywheel loose as shown.


RIGHT WRONG

4. Remove flywheel. After removing flywheel, note position of flywheel key. Key must be installed with the straight edge in a vertical (straight up and down) position. It should not be installed with straight edge parallel to the crankshaft taper. Remove key with a pair of side cutters or dikes.

5. Check flywheel for wear and strength of flywheel magnets. Check keyway for distortion and/or cracks.

6. Flywheel nut should always be torqued properly when flywheel is reinstalled. Correct torque is 375 400 inch pounds (31 33 ft. lbs.). Fly- wheel hub and crankshaft taper must be a h - lutely clean - void of grease and oil.

"F" SERIES (Cont.)

TROUBLE SHOOTING THE "F" ENGINE IGNITION SYSTEM

Mis-firing, no fire, engine dying, o r surging may sometimes be traced to the ignition system. If normal trouble shooting procedures fail to eliminate these symptoms, then the ignition system should be checked using the following guidelines; it is possible that a defective switch o r improper C.D. module ground could also cause these problems.

1. Attach the Test Plug Part No. 426814 to the high tension lead and ground plug to a cylinder fin. The "F" engine C.D. pack must be grounded to run.

2. Attach a 6 inch jumper wire (18 ga. o r larger) to the lower terminal of the C.D. module. (This is the terminal molded into the plastic casing of the C.D. pack). Ground the other end to the cylinder fin.

Do not loop existing C.D. pack ground wire to this terminal.

3. If good spark is evident when cranked, C.D. module is operating properly. Re- move jumper from cylinder fin andground it to the end of the C.D. pack ground lead pig tail at the outer end. If good spark is still evident when cranked, then the switch is possibly defective and should be replaced.

4. If no spark is evident when attaching test lead to C.D. pack ground wire, o r if engine fires intermittently, remove C. D. pack. Look for a bad connection o r a broken ground lead. Clean both sides of the C.D. pack mounting bosses with sand- paper or a scraper.

5. Also check for secure attachment of the high tension lead. This lead should be secured with OMC Adhesive "M" Par t No. 318535 o r G.E. Silicon Sealant.


C-D PACKS D-600 SERIES

PART NO. 681542 MANUAL START

F-SERIES

F SERIES C-D PACK

CLOSED TO RUN TYPE SYSTEM USED ON 1978 THRU 1982 MODELS.

These “F” Series C-D modules are not interchangeable with D-600 Series C-D modules.

PART NO. 681 544 ELECTRIC START SELF CHARGING

PART NO. 683215 GRAY

USED ON 1983 AND LATER COMPLIANT LAWN MOWERS.

I PART NO. 681546 ELECTRIC START

OPEN TO RUN TYPE SYSTEM USED ON ALL COMPLIANT MOWERS.

D-400 SERIES STARTER- SAFETY WARNING

WEAR SAFETY GLASSES WHEN REPAIRING STARTER.

REMOVING STARTER ASSEMBLY To remove the complete starter assembly on D- series engines proceed as follows:

1. Remove engine shroud, primer and fuel hoses.

2. Remove starter rope handle and let rope gradually recoil through the hole in the top of the armature plate.

3. Remove starter mounting bolt on the underneath side of armature plate and take out complete starter assembly. Hold the assembly together, so that the recoil spring isn't accidently released.

J

,400

REPLACING STARTER CORD

To replace starter cord remove the complete starter assembly. Remove retainer ring on the end of the shaft. Remove the nylon starter pinion gear. Note that the pinion gear mounts on the worm gear with the grooved side toward the pulley. Remove three screws holding the pulley plate to pulley. Fit new starter rope into the grooves on pulley as illustrated. Replace pulley plate and tighten three screws down securely. Hold the starter assembly so that the worm gear points toward you, and wind rope clockwise on Pulley.

NOTE

D-400 SERIES STARTER

I E N D O F

S T A R T E R S T A R T E R

SPRING

RETAINER I

I

END OF S T A R T E R S P R I N G

REINSTALLING STARTER ASSEMBLY

To reinstall complete starter assembly, place starter rope retainer on outside of starter cup and insert starter into the armature plate with the protruding. end of the starter spring pointed to the top.

I


When installing a new starter pinion spring it should be stretched only far enough to allow it to snap into the groove of the nylon starter pinion. A distorted spring will not grip the pinion properly and the pinion will not engage the teeth on the flywheel when the starter rope is pulled. The prongs of the starter pinion should be approximately 1/4" or less apart when the spring is off the starter pinion.


STARTER PINION

SHROUD INSTALLATION

The high tension lead comes from the coil between the cylinder and shroud to the spark plug. When installing the shroud on engine, position the high tension lead into the notch in the shroud shield. If the lead wire is not positioned in this notch it can be damaged by jamming it between the shroud shield and cylinder fin.

ROPE BREAKAGE


D=600 SERIES STARTER

SAFETY WARNING

WEAR SAFETY GLASSES WHEN REPAIRING STARTER.

REMOVING STARTER ASSEMBLY

To disassemble starter, pull starter rope out about two feet and tie a slip knot next to rope guide hole. Untie knot securing starter handle, This may require use of two pair of pliers. If you have to cut rope, fuse end to eliminate fraying. Remove starter handle. Pull slip knot out of rope and allow rope to rewind on pulley.

To loosen 7/16 inch screw securing starter assembly to armature plate, carburetor and reed plate assembly must be removed from crankcase. This is necessary because of closeness between this screw and reedplate.

NOTE

Keep dirt out of open crankcase.

Remove starter assembly from armature plate by grasping it between thumb and fingers of both hands. Hold starter assembly firmly together to keep spring loaded pin and cup assembly from separating from star ter pulley. Starter spring is loaded and; potentially harmful if released. Set starter assembly on bench, flat side down.


With starter assembly on bench, flat side down, remove retainer ring with a screwdriver. Remove pinion gear from worm gear.

Never lubricate worm gear keep it clean and dry.

Remove three self tapping screws from starter pulley and remove retainer plate.

SAFETY WARNING


J

There is still tension on starter spring. To remove tension, hold two halves together, pointing shaft downward. Now drop assembly on floor (shaft pointing downward). Halves will separate and release spring. Examine starter spring carefully for bent o r weakened areas. Spring steel is quite brittle and is damaged easily if bent o r twisted. A light coating of grease must be applied before reinstalling.

Re-anchor spring in anchoring channel of


D-600 SERIES STARTER Grasp pin and cup assembly and wrap your fingers over worm gear plate to hold two pieces together. This will keep the spring contained so that you can rotate worm gear in a clockwise manner, winding spring. Continue winding until spring is drawn into cover and end hook rests in recess. Care- fully let spring unwind slowly until it is relaxed.

Pinion spring must be positioned properly during starter assembly installation, one prong goes above armature plate ledge and the other below.

Be sure beveled sharp edge of retainer plate is away from rope. Re-anchor rope and put rope retainer plate on and rewind rope in clockwise fashion. Replace pinion gear and retainer. Starter assembly is now ready to re-install.

Before tightening screw securing .starter assembly make sure that spring end hook faces up and locates in die casted recess in armature plate. Push starter assembly in as far as possible then back out approximately 1/32'' to provide clearance between starter worm gear and magneto plate

7-6

casting.



NOTE

On 1975 and 1976 D-600 Series engines, the magneto plate was redesigned. An "Azdel" (type of fiber- glass) shroud mounting base was added to reduce engine noises.

A dimple in the shroud mounting base located above the hose bracket is used to position the starter assembly.

Before tightening the starter assembly clamping screw, pivot the starter assembly clockwise until top of hose bracket is contacting the bottom of this dimple. Top of the hose bracket should be no more than .020 inch below the dimple. On all 1972 thru 1974, and early production 1975 model D-600 Series engines, slide the starter assembly all the way in, then back it out approximately 1/32" before tightening the starter clamp screw.

Mark a spot on s tar ter pulley and pull enough rope out so that mark rotates approximately two full turns. Grasp starter pulley and spring housing firmly to keep pulley from returning to its relaxed position and wind excess rope around starter pulley.

D-600 SERIES STARTER STARTER ASSEMBLY 1976 MODELS Repair procedures are identical to the preceding in-

formation on D-400 and D-600 series starters. It is A new starter assembly was introduced on necessary to allow .020-.030 clearance between the 1976 models and will be furnished as a service worm shaft and armature plate when reinstalling replacement. the starter.

This assembly includes a new cup and pin and a plastic pulley half and worm shaft. The pinion gear retaining ring is located on the starter pin and secures the entire as- .sembly.

NEW CUP AND PIN RETAINING RING GROOVE

ON PIN

PLATE

NEW PUL

PINION GEAR I NEW R E T A I N I N G

RING


D-400 & D-600 SERIES STARTER STARTER INTERLOCK 1975 AND LATER SELF-PROPELLED MODELS

SAFETY WARNING THE STARTER INTERLOCK ON

SAFETY FEATURE FOR 1975 AND LATER MODELS. THIS SYSTEM PREVENTS STARTING OF THE EN- GINE WITH THE MOWER DRIVE SYSTEM ENGAGED. MISADJUST- MENT OF THE INTERLOCK CAN ELIMINATE THE SAFETY FEA- TURE AND MAKE IT POSSIBLE TO START THE ENGINE WITH DRIVE SYSTEM ENGAGED.

SELF-PROPELLED MODELS IS A

Proper adjustment is accomplished as follows: 1. Disengage drive system by placing han-

dle in "locked out" position. Adjust clutch control rod in the following manner: Loosen clamp screw and with the handle in "lock out" position, pull down on upper clutch rod and up on lower clutch lever until all slack is- removed. Secure the two together with clamp screw. A gap of approximately 3/16 inch should appear between drive rollers and tires.

2. Remove left drive roller guard and left rear wheel. Loosen cable retainer clip and position end of cable housing (with rubber grommet installed on cable) 1-1/2 inches from nearest edge of retainer clip. Secure clip and reinstall drive roller guard and wheel.

3. Place mower handle in “driver” position. Loosen cable housing retainer clip on starter bracket. Place cable housing in groove on starter bracket. Move cable housing forward o r backward in groove until eyelet of inner wire and flat washer contact, surface of black interlock lever. Interlock lever must NOT be moved from its free position. Clamp cable housing onto starter bracket at this location by using cable retainer clip.

4. Check to be certain mower will NOT start (both manual and electric systems) with the handle in "drive" position. Both systems should operate in "neutral" handle position.

5. If further adjustment is required, repeat Step 2.: Remove cable retainer clip at rear axle bracket and place mower handle in "drive" position. Move cable housing forward o r backward until eyelet of inner wire and flat washer contact surface of black interlock lever (opposite end of cable housing). Interlock lever must not be moved from its free position. Clamp cable housing onto rear axle bracket at this location by installing retainer clip. Repeat Step 4.

It is not necessary to readjust interlock system each time the cutting height: is changed but it IS NECES- SARY ;to adjust the control rod each time. See Step 1 for control rod adjustment.

If the clutch lever is adjusted at the rear axle bracket, in order to provide the 3/16- inch gap between the drive roller and rear wheel, then the interlock system must be readjusted.

7-8 REVISED 1977 SERVICE BULLETIN REFERENCES

-"F" SERIES STARTER-

REPLACING STARTER ROPE

Unwind starter rope, rotate pinion gear out against washer and retaining ring. Pull knotted end of rope out using needle nose pliers as shown and untie o r cut knot off.

REMOVING STARTER ASSEMBLY

To remove the complete starter assembly on "F" series engines proceed as follows:

1. Remove' engine shroud, primer and fuel hoses. Disconnect switch leads.

2. Remove starter rope handle and allow rope to gradually recoil through hole in top of the air baffle.

3. Using an Allen wrench loosen the socket setscrew securing starter shaft to engine and remove starter assembly.

“F” SERIES STARTER

Thread new rope through hole, tie overhand knot, pull knot down into the recessed cavity. Wind rope clockwise with the pinion facing you.’ Pigtail on knot must be tucked into cavity as shown.

When installing a new starter pinion spring it should be stretched only far enough to allow it to snap into the groove of the nylon starter pinion. A distorted spring will not grip the pinion properly and will possibly jump off and become lost. The prongs of the starter pinion should be approximately 1/4” or less apart when the spring is off the starter pinion.

A STARTER PINION

ROPE BREAKAGE

Rope breakage or “cutting” can’ normally be attributed to rough surfaces, sharp nicks or edges inside rope guide hole or pulley. Use old piece of rope with grinding compound or other abrasive to smooth sharp surfaces.

“F” SERIES STARTER

Reassemble spring in anchoring channel of pulley and push pin of pin and cup assembly through the pulley opening. Make sure the spring is guided into the slot in cover.

DISASSEMBLY OF STARTER

With starter assembly on bench, flat side down, remove retainer ring with a screwdriver. Remove pinion gear from pulley.

Never ‘lubricate pulley keep it clean and dry.

SAFETY WARNING

THERE IS STILL TENSION ON STARTER SPRING. TO REMOVE TENSION HOLD TWO HALVES TO- GETHE’R, POINTING SHAFT DOWN- WARD. NOW DROP ASSEMBLY ON

WARD). HALVES WILL SEPARATE AND RELEASE SPRING.

FLOOR (SHAFT POINTING DOWN-

Examine starter spring carefully for bent or weakened areas Spring steel is quite brittle and is damaged easily if bent or twisted. A light coating of Lawn-Boy “A” grease must be applied before reinstalling.

7-18 SAFETY RELATED SERVICE BULLETIN REFERENCES

“F” SERIES STARTER Grasp pin and cup assembly and wrap your fingers over starter pulley to hold two pieces together. This will keep the spring contained so that you can rotate pulley in a clockwise manner, winding spring. Continue winding until spring is drawn into cover and hook rests in slot. Carefully let spring unwind slowly until it is relaxed.

Be sure ends of starter pinion spring are hooked on the die cast spring guide of the C.D. bracket.

Check to make sure rope retainer is even with C.D. mounting bracket as shown. Se- curely tighten socket setscrew.

CORRECT STARTER SPRING PRELOAD

If the end of the rope is in segment@ wrap rope by the rope retainer one time.

If the end of the rope is in segment@ wrap rope by the rope retainer twice.

When starter rope is pulled all the way out, the pulley must still turn before bottoming of the recoil spring occurs. Otherwise, recoil spring life will be reduced.

SERVICE BULLETIN REFERENCES .7-19

“F” SERIES STARTER STARTER INTERLOCK- SELF- PROPELLED MODELS

The starter interlock is a safety feature on self-propelled models. This system prevents starting the engine when the control handle is in the “DRIVE” position. The interlock cable is attached to the rear axle and an interlock lever. When the control handle is placed in “DRIVE” position the cable rotates the interlock lever upward

into a position that prevents the starter pinion from engaging the flywheel. When the control handle is placed in “NEUTRAL” position, the interlock cable moves the interlock lever downward, allowing the starter pinion to engage flywheel as shown. This permits starting the engine with the control handle in the “NEUTRAL” position only.

SAFETY WARNING

A MISADJUSTMENT OF THE INTERLOCK SYSTEM COULD ALLOW STARTING OF THE ENGINE WITH CONTROL HANDLE

INJURY SITUATION FOR OPERATOR OR OTHERS. PROPER ADJUSTMENT IS AS FOLLOWS:

IN THE ‘DRIVE” POSITION THUS CAUSING A POTENTIAL

F" SERIES STARTER

1. Place control handle in "NEUTRAL" po- until a gap of 3/16" appears between the sition. Adjust clutch control rod by drive rollers and the rear wheels. loosening clamp and pulling up on lower Tighten clamp as tight as possible with clutch lever and down on upper clutch rod hand pressure.

SAFETY WARNING

IMPROPER TIGHTEN. CLUTCH ROD AND LEVER TION MAY RESULT IN LOSING CONTROL OF THE

2. Remove left drive roller guard and left rear wheel. Loosen cable retainer clip and position end of cable housing (with rubber grommet installed on cable) 1-1/2 inches from nearest edge of retainer clip as shown. Secure clip and reinstall drive roller guard and wheel.

:

NOTE

Check felt wheel washers and replace if necessary.

Do not lubricate the felt washers.

NG OF

PERATOR MOWER.

CONNEC-


3. Place control handle in “NEUTRAL” position. Observe movement of interlock lever. The lever should be in a position that allows the starter pinion to engage the flywheel when the starter handle is pulled. There should be approximately .090 inch between interlock lever and

starter pinion. To adjust, remove spring clip and position interlock cable as shown to allow necessary movement of starter pinion. Hold interlock cable in position, DO NOT allow cable to move, and secure interlock cable to starter bracket with spring clip as shown.

4. Place control handle in “DRIVE” posi- To adjust, remove spring clip and position. Observe movement of interlock tion cable so interlock lever prevents lever. When properly adjusted interlock starter pinion from engaging flywheel. lever will move upward preventing Secure cable with spring clip. s tar ter pinion from engaging flywheel.

“F” SERIES STARTER 5. Check movement of interlock lever in ONLY. Mower should NOT start with control

“NEUTRAL” and “DRIVE” position. Check handle out of neutral position. If additional to be certain mower will start with control adjustment is required repeat steps 3 and 4. handle locked in “NEUTRAL” position

SAFETY WARNING

Check interlock operation whenever drive roller engagement or rear axle adjustment is changed. It is NOT nece- sary to check interlock adjustment when cutting height or handle height has been changed. Clutch ‘control rod will require adjustment when handle height is changed.

6. To replace interlock cable, remove left side drive roller cover and rear wheel. Remove spring clip securing the cable to the .deck and remove cable from rear axle. The interlock lever is designed with a “quick disconnect” feature that allows the cable assembly to be easily removed. Remove spring clip securing cable to starter bracket. Rotate cable approximately 45º counterclockwise and remove cable from in-

terlock lever as shown. Reverse procedure when installing new cable. The washer located on the end of the cable must be installed next to the cable loop to secure cable to interlock lever. DO NOT lubricate interlock lever. DO NOT lubricate interlock cable if cable movement is restricted or cable assembly damaged replace cable.


ELECTRIC START SERVICING D-400 SERIES ENGINE TEAR DOWN

Disconnect high tension lead from spark plug, Disconnect and remove battery. Remove belt cover and V-belt Remove key switch nut, push switch through shroud and lay on mower housing. Remove starter handle, fuel cap, and shroud mounting screws. Remove shroud.

Remove fuel tank and baffle assembly.

NOTE: On self-propelled models the pulley assembly is secured by the two fuel tank bracket mountings screws.

Remove starter motor bracket mounting bolts, slide off starter belt and remove starter motor and key switch as an assembly.

681848

Remove flywheel nut. Use a rubber mallet to loosen flywheel and remove flywheel.

Remove flywheel key. Note: Use a pair of side cutter pliers to roll key out of crank-

REASSEMBLY TIPS D-400 SERIES

Use all new gaskets.

Tighten screws, nuts and bolts Refer to Section torque chart.

Check governor for correct engine RPM adjustment during reassembly. It will take more time to adjust after assembly is completed.

Position key in key way before installing flywheel.

I I

RIGHT WRONG


CHECK STARTER END PLAY

There must be a small amount of "end play" between starter and the outside "E" ring. To bet correct end play, loosen the set screw,

' push the starter and shaft against the magneto plate, insert a .010 feeler gauge between “E” ring and starter. Securely tighten set 'screw.

STARTER BELT TENSION

Proper belt tension is one eighth inch movement with one and one half pounds of pressure.

Loosen 3 mounting bolts and nuts and move starter motor until proper tension of 1 1-1/2 lbs pressure with .156/.125 deflection at center between pulleys is achieved.

Tighten bolts and nuts securely.


~- , I

ELECTRIC START SERVICING D=600 SERIES

The D-600 Series starter assembly, including starter pinion gear is attached directly to crankcase. There is no belt drive involved. The battery is a new compact type, capable of 400 starts without recharging. Starter motor has a no-load speed of 3800 RPM’s, is capable of producing high starting torque needed for starting cold engines or in starting a unit while in heavy grass. Ignition switch (key type) is mounted in battery case cover. It is a true ignition switch, cannot be started manually if key is in off position. Battery charger jack is also mounted in battery case. During winter storage period, it is of utmost importance to check water level and fill if necessary. The battery should be charged once monthly to prevent lead plates from sulfating. Use only the charger (400 MA) that was supplied with mower.

There are three mounting holes in the starter casting as shown. One hole at lower left hand side is the pivot leg, while two other holes are over sized so that an adjustment can be made to enable pinion gear to mesh properly with teeth in flywheel.

To replace pinion spring or gear, metal retaining ring is removed from end of worm gear shaft. No lubrication is recommended on worm gear or pinion gear.

NOTE: When re-installing new retaining ring, it is advisable to use an arbor press to press on securely.

Starter motor, starter pinion gear, worm gear shaft and driven gear assembly are exposed by removing cover plate as shown. A light application of Lawn- Boy “A” grease should be applied to metal driven gears

EARLY PRODUC TION

LATER PRODUCTION AND SERVICE PARTS


“F” SERIES STARTER STARTER DISASSEMBLY Remove retainer ring, pinion stop washer, pinion spring and pinion gear from helix.

85204

SAFETY WARNING

TO PREVENT STARTER SPRING FROM UNWINDING HOLD PULLEY TIGHT AGAINST SPRING AND CUP.

Remove clutch assembly.

Remove starter pulley and spring. USE CAUTION WHEN REMOVING SPRING.

Remove three screws holding the cup assembly to the starter motor. Remove cup. Remove motor pinion, starter gear and thrust washer.

Remove retaining ring securing drag spring and’ drag roller to bracket. Remove roller and spring. When reinstalling drag spring place hook in end of spring through hole located in bracket, this correctly positions drag spring allowing correct pinion engagement when mower is manually started.

Check all of the parts removed for any damage or wear. Examine rewind spring carefully for bent or weakened areas. Spring steel is quite brittle and is damaged easily if bent or twisted. A light coating of Lawn-Boy “A” grease must be applied before reinstalling. Replace any of the parts that are worn or damaged.

r PINION PIN AND CUP

PINION SCREWS ASSEMBLY STOP PINION STARTER GEAR

MOTOR PINION

STARTER


“F” SERIES STARTER STARTER ASSEMBLY Install motor pinion gear onto short (small) motor shaft. Install thrust washer onto long motor shaft. Install large gear onto motor shaft, Lubricate both gears with Lawn-Boy “A” grease. Assemble cup to motor securing it with three cap screws removed in disassembly.

Install rewind spring onto pulley as described on page 7-3 for the manual starter. Position pulley and spring on motor bracket pin locating spring in cup.

NOTE x

Do not attempt to rewind spring at this time.

Install clutch assembly, pinion, pinion spring, stop washer and retaining ring.

With motor shaft facing you, turn starter pulley clockwise pulling rewind spring into cup. Wind rope into pulley clockwise.

Place 1/2 1-1/2 turns tension clockwise on rewind spring. Tie a slip knot in rope permitting it to stop behind rope retainer.

Assemble starter on Engine.

NOTE:

Be sure to place .020-.030 gap between end of helix (worm gear) and crankcase. I

Reconnect all leads starter motor, alternator, key switch cable and battery.

Check starter operation electrically.

TROUBLE SHOOTING THE “F” ENGINE ELECTRIC STARTER

The pinion gear on the electric start models of the “F” engine is activated by inertia. Manual starter engagement is accomplished by a typi- c a l pull through of the starter rope.

2. If starter engages manually, but not electrically (starter motor running), there may be a failure of the metal gears inside gear housing. (Replace broken gear as a set.) Gear Part Numbers are 608034 .- and 610255.

3. If electric motor does not turn at all, check for electrical malfunction or for proper interlock adjustment.

4. After the motor starts, pinion should return to a position near the center of the helix---it should not touch teeth on flywheel, otherwise damage to pinion could occur.

5. Exercise electric start and manual start (actually starting the motor) several times each way before returning mower to service.


“F” SERIES STARTER ELECTRIC STARTER REMOVAL

Remove shroud and air baffle.

Set the alternator air gap. The correct air gap is .010” Position the air gap gauge, part no. 604659, in the gap between the alternator and flywheel. Loosen two cap screws securing the alternator. Ro- tate flywheel; when flywheel magnets are adjacent to the alternator they will pull it in tightly. Secure alternator with the two cap screws. Do not push or pull alternator or flywheel when adjusting.

Disconnect leads from battery, starter motor and alternator. Remove screws securing interlock mechanism to starter frame.


“F” SERIES STARTER Loosen set screw holding starter motor shaft to crankcase cover.

Remove hex cap screws securing starter motor bracket to muffler plate.

Additional allen wrench clearance can be gained by removing carburetor.

Remove hex cap screws securing starter motor bracket to starter frame.

NOTE

Do not try to move starter laterally to either the right or left. It is possible to bend the starter motor shaft.

Carefully slide starter motor and bracket straight out from engine and lift out.

NOTE

The starter motor shaft locates and operates in a loose bushing located in the crankcase casting. This bushing is loose fit into the crankcase. This bushing can slide out and become lost when removing the starter. Check this bushing for wear and damage while the starter is out.

SAFETY WARNING

WITH THE STARTER ASSEMBLY REMOVED, IT IS POSSIBLE FOR CLUTCH AND ROPE PULLEY AS- SEMBLIES TO SLIDE OUT PERMIT- TING STARTER SPRING TO BE RE- LEASED ACCIDENTLY. HANDLE

SEMBLY PROCEDURES CLOSELY. WITH CARE AND FOLLOW DISAS-


SECTION 8 POWERHEAD ENGINE TEAR DOWN AND REASSEMBLY TIPS

D-400 SERIES Refer to Section 14 for special "D" engine tools needed for tear down and reassembly.

Keep assemblies intact whenever possible in tear down. Obseve assembly tips. Refer to Torque Reference Guide Section 16 for correct torque settings dining assembly.

SAFETY WARNING Disconnect high tension lead from spark plug to prevent accidental starting of engine. 1974 AND EARLIER: Disconnect gas

line from carburetor and remove complete engine shroud, gas tank, gas tank bracket, primer bar and air baffle. Replace shroud screws in the same location from which they were removed.

1975 AND LATER: Remove engine shroud mounting screws. Remove the retainer clip from the speed control opening

the shroud and disconnect the fuel line and primer hose from the shroud and fuel tank assembly. Tilt the shroud to maneuver the speed control knob through shroud opening and remove shroud.

in the rear of the shroud. Carefully lift

Remove spark plug and install special piston stop tool No. 677389. This stop will allow easy removal of flywheel nut. Remove flywheel screen and flywheel nut.

I

1975 AND LATER


ENGINE TEAR DOWN AND REASSEMBLY TIPS D - 4 0 0 SERIES

To remove flywheel; lift up on one side and strike top of thick fin on opposite side with soft hammer (plastic or rawhide). Remove flywheel. Check flywheel for damaged fins and keyway for distortion, cracks or damage. Replace if damaged.

Remove four screws securing air baffle to armature plate and remove air baffle.

1975 and later models are equipped with a plastic air baffle. Exercise care when removing assembly from armature plate.

Remove flywheel key. Use a pair of diagonal pliers to roll the key out of crankshaft keyway.

FL

I 1975 AND LATER I

I

RIGHT WRONG

NOTE

Correct installation of key is important.


ENGINE TEAR DOWN AND REASSEMBLY TIPS D-400 SERIES

Lift governor yoke, weights and collar off as an assembly. Set aside carefully. Refer to Section 5 for adjustment and servicing.

NOTE

Reinstall governor assembly with word “KEY” on yoke under crankshaft keyway.

Remove governor spring and steel thrust washer. Refer -to Section 5 for lubrication of thrust washer.

Unhook variable speed spring from governor lever. Lift up on governor lever to disengage prongs from slots in dust cover. Remove governor lever and nylon thrust collar. Refer to Section 5 for proper installation of thrust collar.

Remove by taking screws.

dust cover out three

Push small end of spark advance flyweight toward crankshaft. Hold tension of spring against crankshaft and return flyweight to original position. Allow smaller end of flyweight to drop down. Remove pin and spring.

REASSEMBLY TIP Install flyweight with words “SHAFT KEYWAY THIS END” (smaller end) toward crankshaft keyway. Reinstall pin and spring properly - clip on end must be installed horizontally under flange in narrow end of flyweight.



@Slide flyweight and cam off crankshaft.

Remove three magneto plate mounting screws.

NOTE

Apply Lawn-Boy nut and screw lock part number 682301 to threads of magneto plate mounting screws prior to reassembly. Tighten screws to correct torque, refer to Section 16 for correct torque.

Needle bearings in magneto plates of some models are not retained. To hold them in place during removal, and also to protect the main bearing seal, insert crankshaft guide tool, part number 602887 as shown. Remove armature plate.

A bearing containing 25 needles (largest bearing pictured) was used through 1969 production. A different magneto plate and bearing assembly was

i


ENGINE TEAR DOWN AND !REASSEMBLY TIPS -D-400 SERIES

To replace bearing, remove seal. Insert blade end of screwdriver under seal and pry up. Do not damage the magneto plate casting.

@ Insert bearing removal tool Part No. 605082 and drive bearing out with soft headed hammer. If magneto plate is resting on hard surface, plate may become damaged; therefore, hold plate in palm of hand.

@ Install bearing by inserting bearing on installer tool with lettering facing head of tool. Drive bearing in, holding plate in hand, until tool bottoms on plate, recessing bearing slightly.

BEARING INSTALLER ! PART NO. 605081

After magneto plate has been reassembled on short block, lubricate the new seal and slide it into place on the crankshaft. Place seal installer Part No. 608976 on seal. Drive it in until tool bottoms on top of plate.

NOTE Always replace seal never reuse.

SERVICE BULLETIN REFERENCES REVISED 1977. 0 5


@Remove carburetor and reed plate assembly complete by removing four (4) screws securing reed plate to crankcase.

NOTE The upper left hand screw has no lockwasher. This is to provide clearance between throttle arm and head of screw.

Use a large screwdriver or a socket to loosen (do not remove) the connecting rod screws. Lock tabs have to be bent away from screws first.

NOTE Do not reuse lock tabs. Always replace them with new ones.

Remove four (4) 3/8 inch hex head screws securing cylinder to crankcase. Hit cylinder head sharply with soft headed hammer (plastic or leather) a steel hammer will damage the casting. Remove cylinder by pulling away from piston quickly. This prevents the piston and rings from binding and becoming damaged.

Examine cylinder gasket closely. It may be positioned incorrectly during reassembly. Intake ports can be partially blocked (refer to cylinder on the left) if gasket is reversed. Correct positioning is illustrated on cylinder on the right.

INCORRECT CORRECT 8-6 SERVICE BULLETIN REFERENCES

ENGINE TEAR DOWN AND ‘REASSEMBLY TIPS D - 4 0 0 SERIES

Correct cylinder for D-400 series engine is shown at right. Cylinder a t left (ribs cast in letter “H” form) to be used only on D-600 series engine. If used on D-400 engine, failure will occur.

Position crankcase so piston dome is facing up. Crankshaft should be rotated until journal is at lowest position. Remove rod cap, allowing needle bearings to fall out. Nee- dles should be counted. There must be 33. New lock tabs should be installed on rod cap screws for reassembly.

Remove piston and rod assembly. Note mating marks on rod and cap, and the dovetail ends of the bearing liners. These parts must be mated for reassembly. Liners must be centrally located in rod and cap.

DOVETA ENDS

MATING MARKS

. D - 6 0 0 S E R I E S D-400 S E R I E S

NOTE Engines produced prior to 1970 contained three-ring piston those produced after contained two-rings on piston. The two- ring piston and rod assembly contains 27 loose needles in wrist pin end of rod. The three-ring piston and rod contains a bronze bearing in wrist pin end of rod. Care must be taken in removing wrist pin so that loose needles are not misplaced or lost. A 7/16” diameter x 3/4” dowel rod may be inserted to prevent this. This is of utmost importance, since the needle bearing assembly is not available as a service replacement.

Remove wrist pin retainer rings and drive wrist pin out.

When reassembling connecting rod in piston, the spacer lug is positioned up towards “top” of


piston. NOTE

When replacing retainer rings, opening must face piston dome or towards bottom of piston skirt. This will eliminate retainer rings from popping out during operation. Retainer has beveled side and flat side. When installed, flat side must face outside of piston.

The word “TOP” is diecast in the skirt of the piston; when installed in Cylinder, it must face up.

8-7


Pull crankshaft from crankcase and wipe connecting rod-throw dry. Prepare strip needle bearing, part number 677963 (includes 33 needles) for installation by removing it carefully and position it on index finger. Wrap needles around throw. If old needles are re-installed, apply a coating of OMC needle bearing grease part number 378642 or equivalent on rod cap and rod. Place 17 needles on rod cap and 16 on rod.

Install crankshaft in crankcase. Apply oil to piston, rings, wrist pin, and cylinder sleeve. Place rod on crankshaft journal and install rod cap. Tighten rod cap screws finger tight, i.e., just enough to retain needle bearings. Do not bend lock tabs at this point.

Install ring compressor, part number 610510 over head of piston and compress rings. Place cylin- . der over piston head. Maintain pressure on ring compressor until rings enter cylinder.

NOTE

Check gasket. It must not be covering intake ports. Cylinder must be installed with exhaust ports down.

Center rod on wrist pin. See Section 16 for correct rod cap screw torque (60 inch-pounds), and tighten screws in three steps of 20 inch-pounds each. Rotate crankshaft after each step to check freedom of assembly.

NOTE

Torque rod cap screws, flywheel nut, spark plug, and blade nut according to torque chart in Section 16.


Bend lock tabs up against screw heads. If tabs do not fit flush against side of screw head, do not turn screw merely form tab around corner.

NOTE

Apply a generous amount of oil to the needle bearing and rotate the crankshaft several times to work the oil into the bearing.

ENGINE TEAR DOWN AND ,REASSEMBLY TIPS 0-600 SERIES

SAFETY WARNING BEFORE PROCEEDING WITH DIS- ASSEMBLY, ALWAYS DISCONNECT SPARK PLUG LEAD TO PREVENT ACCIDENTAL STARTING OF EN- GINE. ALSO DRAIN ALL FUEL FROM TANK INTO AN APPROVED SAFETY CONTAINER STORE IN A WELL VENTED AREA.

NOTE

Keep assemblies intact whenever possible in tear down. Observe assembly tips. Refer to Torque Reference Guide (Section 16) for correct torque requirements during reassembly.

1974 AND EARLIER: Place fuel shut off valve in "OFF" position. Disconnect fuel and primer hoses from carburetor. Remove seven screws securing shroud and gas tank assembly and remove shroud.


ENGINE TEAR-DOWN AND REASSEMBLY TIPS UTILITY MODELS

Refer to Section for special "D" engine tools needed for tear-down and reassembly.

SAFETY WARNING BEFORE PROCEEDING WITH DIS- ASSEMBLY, DISCONNECT SPARK

DENTAL STARTING OF ENGINE. ALSO DRAIN ALL FUEL FROM TANK INTO AN APPROVED SAFETY CONTAINER AND STORE IN A WELL VENTED AREA.

NOTE Keep assemblies intact whenever possible in tear-down. Observe assembly tips. Refer to Torque Ref- erence Guide Section 16 for correct torque settings during reassembly.

PLUG LEAD TO PREVENT ACCI-

Remove four (4) engine shroud mounting screws. Carefully lift the shroud and disconnect the fuel line and primer hose from the shroud and fuel tank assembly. Tilt shroud to remove.

Remove spark plug and install special piston stop tool part no. 677389. This will allow easy removal of flywheel nut. Remove flywheel screen. Screen must be removed to expose flywheel nut. Remove flywheel nut.

CAUTION NEVER RUN OR TEST A LAWN-BOY ENGINE WITHOUT THE AIR BAFFLE OR SHROUD IN PLACE. A PISTON SEIZURE WILL OCCUR.

8-16 SERVICE BULLETIN REFERENCES REVISED 1983

ENGINE TEAR-DOWN AND, REASSEMBLY TIPS UTILITY

To remove flywheel; use a soft headed (plastic or rawhide) hammer and strike flywheel wide fins to loosen flywheel. Remove flywheel. Check flywheel for broken fins, damage or cracks.

MODELS

Remove flywheel key. Use a pair of diagonal pliers to roll the key out of crankshaft keyway.

Remove four screws securing air baffle to armature plate and remove air baffle.

NOTE

Utility models a r e equipped with a plastic air baffle. Exercise care when removing assembly from armature plate.


a NOTE

Correct installation of key is important.

8-17

ENGINE TEAR-DOWN AND REASSEMBLY TIPS UTILITY MODELS’

Lift governor yoke, weights and collar Remove dust cover by removing three off as an assembly. Set aside carefully. attaching screws. Refer to Section 5 for adjustment and ser - vicing.

NOTE

Reassembly Tip Reinstall governor assembly with word “KEY” on yoke under crankshaft keyway.

Remove governor spring and steel thrust washer. Refer to Section 5 for lubrication of thrust washer.

Push Small end of spark advance flyweight toward crankshaft. Hold tension of spring against crankshaft and return flyweight to original position. Allow smaller end of flyweight to drop down. Remove pin and spring.


ENGINE TEAR-DOWN AND' REASSEMBLY TIPS MODELS UTILITY

Slide flyweight and cam off crankshaft.

Remove three (3) magneto plate mounting screws.

NOTE

Apply Lawn-Boy nut and screw lock part no. 682301 to threads of magneto plate mounting screws prior to reassembly. Tighten screws to correct torque, refer to Section 16 for correct torque.

Needle bearings in magneto plate are not retained. To hold them in place during removal, insert crankshaft guide tool, part no. 602887 as shown Remove magneto plate.

'TO replace bearing, remove seal using seal remover tool part no. 681867.

SERVICE BULLETIN REFERENCES 8-19 REVISED 1978

ENGINE TEAR-DOWN AND REASSEMBLY TIPS UTILITY

Insert bearing removal tool part no. 605082 and drive bearing out with soft headed hammer. If magneto plate is resting on hard surface, plate may be damaged; therefore, hold plate in palm of hand.

Install bearing by inserting bearing on installer tool with lettering facing head of tool. Drive bearing in, holding plate in hand, until tool bottoms on plate, recessing bearing slightly.

MODELS'

After magneto plate has been reassembled on short block, lubricate the new seal and slide it into place on the: crankshaft. Place seal installer part no. 608976 on seal. Drive it in until tool bottoms on top of plate.

NOTE

Always, replace seal never reuse old seal.

Remove carburetor and reed plate assembly by removing four (4) screws securing reed plate to crankcase.

The upper left hand screw has no This is to provide lockwasher

clearance between throttle arm and head of screw.


ENGINE TEAR-DOWN’ AND REASSEMBLY TIPS UTILITY

Use a large screwdriver or socket to loosen (do not remove) the connecting rod screws. Lock tabs do have to be bent away from screws first.

Remove four (4) 3/8 inch hex head screws securing cylinder to crankcase. Hit cylinder head sharply with soft headed hammer (plastic or leather) a steel hammer will damage the casting. Remove cylinder by pulling away from piston quickly. This prevents damage to piston and ring assembly.

Examine cylinder gasket closely. It may be positioned incorrectly during reassembly. Intake ports can be partially blocked (refer to cylinder on the left) if gasket is reversed. Correct positioning is illustrated on cylinder on the right.

INCORRECT CORRECT

MODELS

Correct cylinder for D-400 series engine is shown at right. Cylinder at left (ribs cast in form of letter “H”) to be used only on D-600 series engine. If used’ on D-400 engine, failure will occur.

600 SERIES 400 SERIES Position crankcase so piston dome is facing up. Crankshaft should be rotated until journal is at lowest position. Remove rod cap, ‘allowing needle bearings to fall out. Needles should be counted. There must be 33. New lock tabs should be installed on rod cap screws for reassembly.

Remove piston and rod assembly. Note mating marks on rod and cap, and the dovetail ends of the bearing lines. These parts must be mated for reassembly Liners must be seated in rod and cap correctly.

SERVICE BULLETIN REFERENCES REVISED 1978

ENGINE TEAR-DOWN AND REASSEMBLY TIPS UTILITY

Remove wrist pin retainer rings and drive wrist pin out. To remove wrist pin use special tool part no. 602884.

When reassembling connecting rod in piston, the spacer lug is positioned up towards "top" of piston.

NOTE When replacing retainer rings, opening must face piston dome or towards bottom of piston skirt. This will eliminate retainer rings from popping out during operating. Retainer has beveled side and flat side. When installed flat side must face away from wrist Din.

NOTE The word "TOP" is diecast in the skirt of the piston; when installed in cylinder, it must face up.

Pull crankshaft from crankcase and wipe connecting rod-throw dry. Prepare stripe needle bearing, part no. 677963 (includes 33 needles) for installation by removing it carefully and position it on index finger. Wrap needles around throw. If old needles are re-installed, apply a coating of Needle Bearing Grease part no. 378642 or equivalent on rod cap and rod. Place 17 needles on rod cap and 16 on rod.

MODELS

Instali crankshaft in .crankcase. Apply oil to piston, rings, wrist pin, and cylinder sleeve. Place rod on crankshaft journal and install rod cap. Tighten rod cap screws finger tight, i.e., just enough to retain needle bearings. Do not bend lock tabs at

Stagger ring gaps (ends) on top of piston approximately 30° apart and install ring compressor, part no. 426020 over head of piston and compress rings. Place cylinder over piston head. Maintain pressure on ring compressor until rings enter cylinder.

NOTE

Check: gasket. It must not be covering intake ports. Cylinder must be installed with exhaust ports down.


ENGINE TEAR-DOWN AND REASSEMBLY TIPS UTILITY MODELS

Center rod on wrist pin. See Section 16 for Bend lock tabs up against head of each screw. correct rod cap screw torque (60 inch-pounds) and If tabs do not fit flush against head of screw, do tighten in three steps of 20 inch-pounds each. not screw merely form tab around corner. Rotate crankshaft after each step to check freedom of assembly.

NOTE

Torque rod cap screws, flywheel nut, spark plug and blade nut according to torque specifications in Section 16.

NOTE


PISTON AND CYLINDER WALLS SCORING Most instances of piston & cylinder scoring can be traced to lack of oil, use of improper oil fuel mixture, foreign particles in cylinder, heating caused by plugged cooling fins, or excessive carbon build-up in the cylinder exhaust ports.

Piston A has been used in an engine which has a correct fuel-oil mixture. Note there is no sign of scoring, the rings are free in their grooves, and the top of the piston shows dark discoloration which is normal.

Piston B was also used in an engine with the correct fuel mixture, but was scored after a few minutes or possibly several hours of operation. The top of the piston is dark in color, which is normal. Also, a film of oil is found in the ring grooves and on the inside of the piston which further indicates proper fuel-oil mix. Note the scoring is isolated to a particular area on the piston skirt. Scoring is always adjacent to either the intake or exhaust ports. This resulted from small particles of metal breaking away from an intake or exhaust port. This type of failure is covered by warranty.

Piston C is heavily scored all around the skirt. This piston was run in an engine with a lack of lubrication. The light color on the top of the piston and lack of oil inside the piston and ring grooves indicates lack of oil. This i s not covered by warranty.

Lack of lubrication scoring will not always result in light coloration of the piston dome as the engine may have been run for some time with sufficient lubrication and consequently, the piston dome will be dark in color and resemble one which has been operating on proper fuel mix.

Piston D is scored as a result of carbon build-up. Accumulation of carbon and other deposits on the piston skirt. Particles of carbon breaking away from the exhaust ports , lodging between the piston skirt and cylinder results in scoring the piston and/or cylinder. This is not covered by warranty.

A

B

SCORING DUE TO LACK

OF OIL

D

CARBON

In most cases, the rings will be partially or completely frozen within the ring grooves, and the piston will be discolored.

Carbon scoring usually results from the use of a low grade oil or an excessive amount of oil in the mix or a lack of care and maintenance which is owner's responsibility.


REVISED 1978


Bend lock tabs up against screw heads. If tabs do not fit flush against side of screw head, do not turn screw merely form tab around corner.

NOTE


ENGINE TEAR DOWN AND ,REASSEMBLY TIPS 0-600 SERIES

SAFETY WARNING BEFORE PROCEEDING WITH DIS- ASSEMBLY, ALWAYS DISCONNECT SPARK PLUG LEAD TO PREVENT ACCIDENTAL STARTING OF EN- GINE. ALSO DRAIN ALL FUEL FROM TANK INTO AN APPROVED SAFETY CONTAINER STORE IN A WELL VENTED AREA.

NOTE

Keep assemblies intact whenever possible in tear down. Observe assembly tips. Refer to Torque Reference Guide (Section 16) for correct torque requirements during reassembly.

1974 AND EARLIER: Place fuel shut off valve in "OFF" position. Disconnect fuel and primer hoses from carburetor. Remove seven screws securing shroud and gas tank assembly and remove shroud.


ENGINE TEAR DOWN AND REASSEMBLY TIPS 0-600

1975 AND LATER: Remove shroud mounting screws. Lift shroud from engine and disconnect primer hose and fuel line from shroud and fuel tank assembly.

1974 AND EARLIER: Remove three screws securing air baffle to armature plate. Disconnect kill switch lead from ignition switch and remove air baffle.

1975 AND LATER: Remove two Phillips head screws and the ON-OFF switch mounting screw, disconnect switch wire and remove air baffle.

C ENGINE WITHOUT THE AIR BAFFLE OR SHROUD IN PLACE. WITHOUT THEM A PISTON SEIZURE WILL OCCUR.

CAUTION; NEVER RUN OR TEST A LAWN-BOY

SERIES

Remove spark plug and install piston stop tool no. 677389. This stop will allow easy removal Of flywheel nut. Remove flywheel nut.

To remove flywheel; first remove flywheel screen. Use a soft headed (plastic or rawhide) hammer and strike top of wide fin of flywheel. At the same time apply upward pressure with your hand at point opposite where hammer strikes. Loosen flywheel as shown. Examine flywheel for wear or damage. Check keyway for distortion or cracking.


ENGINE TEAR DOWN AND REASSEMBLY TIPS D-600' SERIES

1975 AND LATER: Remove shroud mounting base by removing three 7/16 inch hex head screws. One of these screws is located under C-D module. Remove C -D module to facilitate shroud mounting base removal. On models equipped with alternator remove two alternator mounting screws and remove alternator.

NOTE

The spark plug lead is routed between the cylinder and shroud mounting base. Use care when removing C-D module to prevent damaging the spark plug lead or rubber connector.

NOTE

Remove flywheel key. Use a pair of diagonal pliers to roll key out of crankshaft keyway.

Correct installation of key is important. If installed incorrectly, possible cracking of flywheel hub may occur.

Lift governor yoke, weights and collar off as an assembly. Set aside carefully. Refer to Section 5 for adjustment and ser- spring from governor vicing. lever. Lift up on governor lever to disengage prongs

from slots in bracket. Remove governor lever and nylon governor collar. NOTE

Reinstall governor assembly with NOTE word "KEY" on yoke facing crank- Refer to Section 5 for proper installation shaft keyway. of governor collar.

Remove governor spring and steel thrust washer. Refer to Section 5 for lubrication Remove three magneto plate mounting of thrust washer. screws.



Install crankshaft guide tool, Part No. 602887 on top of crankshaft. This will retain the loose needle bearings in the magneto plate. Remove magneto plate and bearing assembly.

NOTE

when reassembling magneto plate, coat threads of mounting screws with Lawn- Boy nut and screw lock part no. 682301 and tighten securely. Refer to Section 16 for correct torque.

To replace bearing, insert bearing removal tool Part No. 605082 in top of bearing and drive it out with a soft headed hammer. Hold plate in palm of your hand. If the needle bearings fall out of bearing race, count them and reinstall in bearing race by using a heavy grease. Check bearing name, stamped on bearing. If Torrington, it has thirty-three needles; if Bremen, it has thirty-two needles.

To install the bearing, insert bearing installer tool Par t No. 605081 with the lettering facing the head tool. Drive bearing in until the tool bottoms on plate. This will recess bearing slightly.

NOTE

Hold armature plate in hand when removing or installing bearing. This will prevent armature plate damage. .-

After magneto plate has been reassembled on short block, lubricate the new seal and slide it into place on the crankshaft. Place seal installer part no. 608976 on seal. Drive it in until tool bottoms on top of plate.

NOTE

Always replace seal never reuse old seal.

Remove carburetor and reed plate assembly complete by removing four screws securing reed plate to crankcase.

Use a large screwdriver or socket to loosen connecting rod screws. Do not remove them.


ENGINE TEAR DOWN AND ‘REASSEMBLY TIPS D-600 SERiES

Remove four 3/8 inch hex head screws securing the cylinder to crankcase. Hit the cylinder head sharply with a soft headed hammer do not use a steel hammer be-

Remove cylinder by pulling it away from piston quickly. This prevents damage to piston and rings.

Examine cylinder gasket closely. It may be positioned incorrectly during reassembly. That is, intake ports (see cylinder to the left) can be partially blocked if gasket is reversed. Correct positioning is illustrated on cylinder to right.

INCORRECT

The D-600 series C-D engine uses a high compression cylinder which cannot be interchanged with cylinder on the D-400 engine. If new D-600 cylinder is installed on D-400 engine it is very likely that piston seizure would occur because of excessive heat. The new D-600 cylinder is pictured at left and can be easily identified by the ribs cast in form of letter “H” in cylinder.

D’-600 SERIES D-400 SERIES I The crankshaft should now be rotated until

rod cap is at lowest position. The rod cap may now be removed, allowing the needle bearings to fall out. Needles should be counted. There must be 33. Examine them carefully to make sure they are not worn or damaged or have flat spots.

Remove piston and rod assembly. Note mating marks on the rod and cap and the dovetail ends of the bearing liners. ,These parts must be mated accordingly for- reassembly. Liners must be centrally located in rod and cap.

CORRECT

Remove wrist pin retainer rings and drive wrist pin out. The connecting rod contains 27 loose needles and care must be taken in removing the wrist pin so that loose needles a re not lost. A 7/16 inch diameter by 3/4 inch dowel rod may be inserted to prevent this. Bearing replacements are not available. Must be purchased as part of rod and bearing assembly.

The retainer ring opening must face the piston dome o r piston skirt. This will eliminate rings from popping out during operation. Also, retainer has a beveled side and flat side. When installed, flat side should face away from wrist pin.

The word "TOP" is diecast in skirt of piston; when installed in cylinder, it must face up.

The strip bearing shown, no. 677963, is rod- journal bearing. It includes 33 individual needles. Pull the crankshaft from the crankcase and wipe connecting rod throw dry. Now, prepare strip needle bearing for installation by removing it carefully from card and position it on your index finger. Wrap needles around throw. If the old needles are

reinstalled, apply a coating of OMC needle bearing grease part no. 378642 or equivalent on the rod cap and rod. Place 17 needles on rod cap and 16 on rod.

When reassembling connecting rod in piston, the spacer lug is positioned up towards "top" of piston.

Install crankshaft in crankcase. Reinstall thrust washer in crankcase of early models self propelled engine. On later models this thrust washer was die cast , i n crankcase. Apply oil to piston rings, wrist pin, and cylinder sleeve. Now gently place rod on crankshaft journal and install rod cap. Install new lock tabs on rod cap screws and install screws and tighten just enough to retain needle bearings. Do not bend lock tabs a t this time.



Stagger ring gaps (ends) over top of piston and install ring compressor, no 610510, over head of piston and compress rings. Place cylinder over piston head. Maintain pressure on ring compressor until rings enter cylinder.

NOTE Check gasket. It must not cover intake ports.' Also, cylinder must be installed with exhaust ports down.

Center rod on wrist pin. Consult Chapter 16 for correct rod cap screw torque 60 inch-pounds, and tighten in three steps of 20 inch-pounds each. Rotate crankshaft after each step to check freedom of assembly.

NOTE

The rod cap screws, flywheel nut, spark plug, and blade nut must be torqued according to torque chart. See Chapter 16 for correct torque.

NOTE

Apply a generous amount of oil to the needle bearing and rotate the crankshaft several times to work the oil into the bearing.

Bend lock tabs up against head of each screw. If tabs do not fit flush against side of screw head, do not turn screw, form tab around corner.








A

B

SCORING DUE TO LACK

OF OIL

D

CARBON




REVISED 1978







A

B

SCORING DUE TO LACK

OF OIL

D

CARBON




REVISED 1978

SECTION 8 POWERHEAD- ENGINE TEAR DOWN AND REASSEMBLY TIPS

“F” SERIES

ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES SAFETY WARNING

BEFORE PROCEEDING WITH DIS- ASSEMBLY, DISCONNECT SPARK

DENTAL STARTING OF ENGINE. ALSO DRAIN ALL FUEL FROM TANK INTO AN APPROVED SAFETY CONTAINER AND STORE IN A WELL VENTED AREA.

PLUG LEAD TO PREVENT ACCI-

NOTE

Keep assemblies intact whenever possible in tear down. Observe assembly tips. Refer to Torque Reference Guide (Section 16) for correct torque settings during reassembly.

1. Move fuel valve to the “OFF” position. Remove shroud mounting screws. Raise shroud slightly and disconnect the fuel and primer hoses from carburetor. Next disconnect the 2 switch leads from the CD pack.

8-26

3. Remove: five Phillips screws securing air baffle. Remove air baffle.

4. Remove carburetor air cleaner cover and the filter element. Remove two Phllips screws securing carburetor and remove carburetor.

NOTE

When removing carburetor be careful not to damage the governor air vane assembly.


ENGINE TEAR DOWN AND REASSEMBLY TIPS "F" SERIES 5. Remove spark plug. Install piston stop tool no.

677389. Rotate flywheel counter clockwise until piston comes up against the stop. This stop will allow easy removal of flywheel nut.

6. With a 11/16'' socket wrench remove flywheel nut. Remove flywheel screen.

7. To remove flywheel; use a soft headed (plastic or rawhide) hammer and strike the top of a thick flywheel fin. At the same time apply upward pressure with your hand at point opposite where hammer strikes. Loosen flywheel as shown. Examine flywheel for damage. Check keyway and hub for distortion or cracking.

8. Remove flywheel key. Use a pair of diagonal pliers to roll key out of crankshaft keyway.

NOTE

Correct installation of key is important.


RIGHT WRONG

SERVICE BULLETIN REFERENCES REVISED 1978. 8-27

ENGINE TEAR DOWN AND REASSEMBLY :TIPS “F” SERIES 9. Remove shroud base.

10. With an Allen wrench loosen the socket set screw securing the starter. Remove the starter.

11. Remove the CD module.

12. Use a socket wrench to remove the two cap screws ‘securing the CD mounting bracket. Remove the CD mounting bracket.

8-28 .REVISED 1978. SERVICE BULLETIN REFERENCES

ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES 13. Using a 1/2” socket wrench remove the four

capscrews holding the crankcase halves together.

14. Turn short block so the side with the alignment pin faces you. Place a wide bit screwdriver in the slot next to the pin. Carefully split the crankcase by twisting the screwdriver bit.

15. Remove connecting rod capscrews, lock plates and rod cap. Discard the lock plates, never reuse them. Remove connecting rod needle bearings. Count them, there should be 33 needles. If they are to be reused, inspect for damage, wear, scoring, overheating, etc.

LOW MAIN

BEARING

CONNECTING CRANKSHAFT ROD -__-

16. &move crankshaft, bearing and seal assemblies from crankcase. Remove bearings and seals from crankshaft. Discard seals, never reuse them.

Inspect main bearings for damage, wear, freedom of movement etc. Replace if questionable.

17. Remove piston and connecting rod assembly from cylinder.

NOTE

The top r ing can fall off the piston during handling.

Remove both rings and inspect for wear damage or sticking. Always replace if they are questionable.

Thoroughly clean crankcase sealing surfaces with Lad-Boy Engine Tuner Part No. 610738.

SERVICE BULLETIN REFERENCES REVISED 1978. 8-29

ENGINE TEAR DOWN AND REASSEMBLY :TIPS "F" SERIES

NOTE

The intake plugs do not have to be removed. If removed, apply Lawn-Boy nut and screw lock Part No. 682301 to the outside surface of them. Use special tool # 609964 to reinstall them.

The photo above illustrates the difference between the connecting rods from the "D"

and "F" ser ies engines. Note that the "D" series rod is slightly shorter than the "F" ser ies connecting rod. These connecting rods interchangeable between the two engines.

The photo below illustrates the difference between the crankshafts from the "D" series engine and the "F" series engine. The crankshafts for the "D' series engine are longer than the crankshafts for the "F" series engines and are not interchangeable.

"F" SERIES ENGINE ENGINES ENGINE

The photo below illustrates the difference between the piston and rings for the "D" and "F" ser ies engines.

The ring grooves in the piston for the "F" series engine are closer to the top of the piston. The top ring


ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES groove in the “F” series piston is narrower than the top groove in the “D” series piston. The piston and ring assemblies are not interchangeable.

The illustration below shows the principal of the pressure back top ring.

CYLINDER

PISTON RING

The illustration below compares the pressure back ring with a regular compression ring.

REGULAR COMPRESSION RING

RING

CHECKING REED ASSEMBLY

Exercise care in handling reeds, so as not to distort them. Bent or distorted reeds must be replaced.


Check for excessive clearance between reed tip and reed seat. Maximum allowed clearance .015 inch. Use an “L” shaped wire type feeler gauge to check this clearance.

Reeds must be installed with rough edge away from seat.

NO. 384848 TO REED PLATE MOUNTING SCREWS

-.I-- ” ~ __

In the reassembly of the connecting rod and cap, the mating marks have to be together. Also the dovetail ends of the liners have to be mated as shown below.

MATING MARKS

DOVETAIL ENDS

If the connecting rod or liners are not assembled correctly, an engine failure will OCCUR

SERVICE BULLETIN REFERENCES .REVISED 1978 8-31

ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES With a pair of compression type pliers #303857 remove the wrist pin retaining rings.

I RETAINING

NOTE

The retainer rings have a beveled side and a flat side. When installed, the flat side should face away from wrist pin.

The retainer: ring opening should face the piston dome or bottom of skirt. This will help to eliminate rings from popping out during operation.

CORRECT INSTALLATION OPEN END UP

Using special tool #602884 drive wrist pin out.

ENGINE TEAR DOWN AND REASSEMBLY TIPS "F" SERIES Check piston, wrist pin, connecting rod, bearings etc. for wear and damage. Replace any worn, damaged or questionable parts.

Reassemble piston, wrist pin and connecting rod by reversing disassembly proceedure.

Install the piston rings onto the piston. The ring with the bevel must be installed in the top groove with the bevel to the top of the piston.

Stagger ring gaps (ends) a s shown. Assem- ble special ring compressor tool part #609967 in crankcase.

RING

NOTE

Top ring can come off piston during handling.

Install piston stop part #677389 in cylinder. This will prevent piston and ring assembly from going too deep into cylinder.

NOTE

If piston goes too deep into cylinder the top ring can drop off of the end of cylinder sleeve and become impossible to remove without damage occurring.

Apply oil to piston rings, wrist pin and cylinder sleeve. Carefully slide piston and rings into cylinder.

NOTE

The word "BTM" is diecast in the skirt of the piston; when installed in cylinder, it must face down towards exhaust ports.

Install liners into the connecting rod and cap. Make sure the dovetail matches up.

Wipe the connecting rod throw of crankshaft dry. Replacement needle bearings part #677963 (33 needles) are attached to a card. They are secured to


ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES the card with clear plastic. To remove them, use a knife to cut the plastic along each side and across each end. Carefully peel the plastic from the strip without disturbing the bearings. They are stuck together with a substance on the lower side. Pick the strip up and lay on your index finger with the substance up. Wrap them onto the crankshaft throw. They should stick and remain in place. Use care in handling so none of the bearings fall off and into the cylinder. If old needles are re-installed, apply a coating of OMC needle bearing assembly grease on the rod and cap. Place 17 needles in the rod cap and 16 in the rod.

Lubricate and assemble main bearings on upper and lower crankshaft journals, lettered end out. Lay crankshaft and main bearing assembly in crankcase guiding connecting rod over needle bearings.

Torque connecting rod screws to 20 inch pounds. Check if crankshaft turns freely or if there is any grinding noise: from the needle bearings.

!

If crankshaft movement is okay, tighten them to 40 inch pounds torque. Rotate crankshaft again to check freedom of assembly. If okay, tighten to 60 inch pounds. Bend lock tabs up against heads of screws.

Lubricate wrist pin, main and connecting rod bearings with oil. Position both main bearings.

NOTE

Be sure dowels on bearings are positioned in notches of cylinder and crankcase.

NOTE : :

DO NOT DISTURB NEEDLE BEAR- INGS. Install connecting rod caps. Align the assembly marks on the connecting rod and cap. Install lock plates and cap screws on connecting rod. Hold lock plates with square tabs out and tighten screws finger tight.

8-34 REVISED 1978. SERVICE BULLETIN REFERENCES

ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES Apply a few drops of Lawn-Boy gasket maker # 682302 to crankcase cover sealing surface.

Smooth sealant over entire surface with your finger. Final appearance of applied sealant should be very (paper) thin.

NOTE :

KEEP BEARINGS AND SEALS FREE OF SEALANT.

Position alignment hole in crankcase cover over alignment pin in crankcase. Install crankcase cover.

CRANKCASE

Tighten cap screws finger tight. Alternately torque cap screws to 60 inch pounds. Rotate crankshaft to check freedom of assembly. Complete torquing of cap screws to 100 to 120 inch pounds. Check for freedom.


ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES Install upper and lower crankshaft seals using special tool part #608976.

Assemble CD mounting bracket.

Install starter assembly. Tighten ALLEN set screw.

Install shroud mounting base.

Thoroughly clean crankshaft taper and flywheel hub. Check key for burrs and install in crankshaft. Refer to page 8-3 for correct positioning. Install flywheel lockwasher and nut. Torque flywheel nut 31 to 33 foot pounds.

Install air baffle and recheck freedom of air vane. If interference occurs, reposition air baffle and/or shroud mounting base.

Assemble starter pull handle on rope. Tie an overhand knot in end of rope.

Before attaching engine shroud, guide starter rope and handle through hole in shroud. Assemble primer hose and fuel line to carburetor. Reconnect switch leads to CD Pack and slide both switch leads under the retaining clip on the air baffle.

NOTE

Failure to secure these switch leads would possibly permit them to become damaged or cut by the starter assembly.

Using the test plug check for spark. Install spark plug. Do not attach spark plug lead until you are ready to test,

Remove engine from holding fixture. Assemble the muffler plate to the engine using a new exhaust gasket. The, two (2) short screws located in holes near exhaust outlet and 2 long ones in other holes. Refer to Section 16 for torque requirements.

Reinstall muffler and crankshaft support to mower. Use special tool part no. 609968 to correctly align crankshaft support.

Install CD pack and set air gap .010 inch.

Install carburetor and check freedom of air vane movement.

Guide end of starter rope through hole in air baffle.

SAFETY WARNING

WHEN REASSEMBLING MUFFLER COVER, ASSEMBLE FASTENERS

GAGE PREVIOUSLY FORMED THREADS. DO NOT FORCE REIN- STALLATION AS THE SCREW WILL FORM A NEW SET OF WEAKER

TUALLY STRIP AND THE SCREW MAY BECOME A THROWN OBJECT.


THREADS WHICH MAY EVEN-

TORQUE TO 140-170 INCH LBS. 8-36 I a REVISED1978 SERVICE BULLETIN REFERENCES

ENGINE TEAR DOWN AND REASSEMBLY TIPS “F” SERIES

NOTE:

OMC Ultra-Loc part no. 388517 or Loctite #271 should be applied to threads of all fasteners (screws, nuts) located under blade housing.

Reinstall adapter hub, blade stiffener (washer on 20” and 21” models), blade and blade nut. Torque blade nut to 50 ft. lbs. Replace spark plug and r e connect high-tension lead.

For testing, move the unit to a well ventilated area. Place fuel in tank, open valve, prime the carburetor (one or two strokes), and start the engine. Permit it to run and warm up (3 to 5 minutes) before making adjustments. At high speed (normal) it should run between 3100-3300 R.P,M. Adjust the governor if necessary to obtain the correct engine speed. Refer to Section 4 for governor adjusting.

SAFETY WARNING

DO NOT PERMIT IT TO OPERATE ABOVE 3300 R.P.M. HIGH ENGINE SPEED (BLADE SPEED) INCREASES POTENTIAL HAZARD OF THROWN FOREIGN OBJECTS WHEN STRUCK BY CUTTING BLADE.


ADJUSTMENTS HANDLE HEIGHT The handle height can be adjusted to a high or low position. This is determinedby which set of holes in the lower handle are used to attach the handle to the handle bracket.

NOTE Self-propelled models: Loosen and separate clutch control rod before attempting to change handle height position.

SAFETY WARNING REPLACE LOCK PINS AFTER AD- JUSTMENT AND MAKE SURE BOTH

TACTS HANDLE BRACKET UPSTOP. A LOOSE HANDLE, OR IMPROPER FUNCTION OF THE UPSTOP MAY CAUSE LOSS OF O P E R A T O R CONTROL.

CUTTING HEIGHT

SIDES OF LOWER HANDLE CON-

SAFETY WARNING DO NOT ATTEMPT TO ADJUST CUTTING OR HANDLE HEIGHT WITH ENGINE RUNNING BECAUSE

TATING BLADE. OF POSSIBLE CONTACT WITH RO-

COMMERCIAL MODELS (EARLY MODELS) All four wheels are adjustable. With a range of cutting heights in 1/2 inch steps from 1 to 4 inches. To adjust, remove wheel bolts and reinsert in the proper height holes. Be su re when adjusting height of cut to install all wheel axle bolts at same height.

Tighten mounting wheel bolt and nut securely.

LEFT HANDLE BRACKET ILLUSTRATED

1. Low Handle Hole 2. High Handle Hole 3. Normal Operating Position 4. Handle Bracket Upstop 5. Storage Position 6. Lock pin


ADJUSTMENTS (CONT)

PUSH MODELS These models a r e equipped with 6-position instant cutting height adjustment from inch to 3 inches as illustrated. The four wheels a r e adjusted individually by a single lever. To change cutting height, simply pull the wheel adjusting lever toward wheel slightly and move either forward or backward to desired position. Release the lever and seat it securely in notch. SET ALL WHEELS AT SAME HEIGHT.

SELF-PROPELLED MODELS NOTE

For self-propelled models: Loosen clutch control rod before attempting to adjust rear wheel height.

The front wheels are adjusted individually (See PUSH MODELS) while the rear wheels are controlled by an adjustment lever with numbers corresponding to the front wheels. SET ALL WHEELS AT SAME HEIGHT.

SAFETY WARNING

SELF-PROPELLED MODELS. WHEN WHEEL OR HANDLE HEIGHT IS CHANGED, THE CLUTCH CONTROL ROD MUST BE READJUSTED FOR

TERLOCK ASSEMBLY. PROPER OPERATION OF THE IN-

CLUTCH CONTROL ROD-SELF- PROPELLED MODELS (REFER TO SECTION 10)

With handle in "locked-out" position, pull down on upper clutch rod and up on lower clutch lever, until all slack is removed. A gap of 3/16" should appear between drive rollers and tires. Secure the two together with clamp screw as tight as possible with hand pressure.

SAFETY WARNING

2-1/4”

1-3/4”

1-3/8”

1

PUSH AND SELF-PROPELLED FRONT WHEEL ILLUSTRATED I

IMPROPER T I G H T E N I N G OF CLUTCH ROD AND LEVER CON- NECTION MAY RESULT IN OPERA- TOR LOSS OF DRIVE CONTROL MECHANISM.

/- --e- /

9.2 SERVICE BULLETIN REFERENCES

ADJUSTMENTS (CONT)

STARTER INTERLOCK-SELF PROPELLED MODELS

The starter interlock is a safety feature on self-propelled models. This system prevents starting the engine when the control handle is in the “DRIVE” position. The interlock cable is attached to the rear axle and an interlock lever. When the control handle is placed in “DRIVE” position the cable rotates the interlock lever upward into a position

“DRIVE” POSITION

that prevents the starter pinion from engaging the flywheel. When the control handle is placed in “NEUTRAL” position the interlock cable pulls the interlock lever downward, allowing the starter pinion to engage flywheel as shown. This permits starting the engine with the control handle in the “NEUTRAL” position only.

“NEUTRAL” POSITION

Misadjustment of the interlock system will eliminate the safety feature it was designed for and may prevent starting the engine with control handle in “DRIVE” position causing possible injury to operator.

For detailed adjustment procedure refer to Section 7.

SERVICE BULLETIN REFERENCES 93

ADJUSTMENTS (CONT)

ALTITUDE NEEDLE ADJUSTMENT





3. Place speed control lever in LOW SPEED running position (2400-2600 R.P.M.)

4. Slowly turn altitude needle (counterclockwise- rich: clockwise-lean) until engine

5.

6. After carburetor adjustment is completed, shut off engine. IMMEDIATELY attempt to restart engine. DO NOT PRIME A HOT ENGINE. It should start within 2 pulls on starter handle. Check starting engine at both HIGH and LOW speed settings. If difficult to restart, turn altitude needle 1/8 turn counter clockwise to richen fuel mixture to obtain easy restarting.

The governor will control the amount of fuel entering the engine. The purpose of the atmospheric pressure adjusting needle is to mix the right amount of fuel with the correct amount of incoming air.

is running smoothly. Allow engine to run for one or two minutes to make sure Refer to Section 4 for complete Fuel adjustment is not too lean. System' information.

Place speed control lever in HIGH SPEED running position (3100-3300 R.P.M.) Observe engine operation. If not running smoothly, turn altitude needle (counterclockwise- rich: clockwise-lean) approximately 1/8 turn at a time to obtain proper engine operation.

NOTE

Never operate the mower with the altitude needle adjusted to less than 1/4 turn from the seat. This will permit a lean mixture (fuel and air) to enter the engine resulting in higher than normal operating temperatures thus causing a scoring condition of the piston, rings and cylinder.



FLOAT ADJUSTMENT

FLOAT SETTING

Remove float bowl and gasket. Invert carburetor. With float arm res t ing on float valve needle, the top of float should be 7/16-15/32 inch above edge of carburetor body as shown. Obtain measurements at two points at right angles to each other. Check hinge on float a r m to be su re it is secured to pin. Use needle nose pliers and tighten hinge as shown.

ADJUSTMENTS (CONT)

Before securing (clamping) the float hinge on the pin, be sure the hinge is centered on the pin and the pin is centered in the carburetor. If not centered, it is possible for the float to stick resulting in carburetor flooding.

If adjustment is required; using needle nose pliers bend float a rm as shown. DO NOT bend float a r m by applying pressure to float.

SERVICE BULLETIN REFERENCES e 9 5 REVISED 1983

ADJUSTMENTS (CONT)


ADJUSTMENTS (CONT)

SAFETY WARNING GOVERNOR ADJUSTMENT SHOULD

SIVE ENGINE SPEED WILL LOOSEN OTHER MOWER COMPONENTS, WHICH MAY BECOME THROWN OBJECTS.

Engine speed (R.P.M.). is controlled by the governor spring tension. All mowers are run and tested at the factory, however, if the governor requires adjustment proceed as follows. 1. Grasp the hex shaped adjusting collar

and gently raise collar upwards until collar is above splines on speed control lever as shown.

2. Rotate adjusting collar counterclockwise to increase spring tension (increase engine R.P.M.). Rotating collar clockwise decreases spring tension (decreasing engine R.P.M.). Reinstall adjusting collar to speed control lever.

NOT EXCEED 3300 R.P.M. EXCES-

NOTE Each spline on the speed control lever represents 50-75 R.P.M.

3. Use a tachometer to accurately measure engine R.P.M. Correct R.P.M. is 2400- 2600 LIGHT speed setting and 3100-3300 NORMAL setting.


NOTE Each click of governor collar represents approximately 50-75 R.P.M.

1. Rotate adjusting collar clockwise to increase spring tension (increase engine R.P.M.). Rotat- ing collar counterclockwise decreases spring tension (decreasing engine R.P.M.)

2. Same as No. 3 above. 3. Same as No. 4 above.

ENGINE SURGING Engine surging will result if governor air vane movement is limited or restricted. When carburetor and air vane assembly are secured to engine check air vane movement within "cut out" area of shroud mounting base. Air vane should move freely through the f u l l throttle range without rubbing or binding within the "cut out" a rea of the shroud mounting base. If binding occurs, loosen shroud mounting bolts and relocate shroud mounting base until resistance is eliminated. Check a i r vane movement with air baffle secured to shroud 'mounting base. The air baffle must be correctly installed to allow the governor air vane to move freely within the air baffle "tunnel." With air baffle secured check movement of air vane. Air vane must not rub or bind against air baffle, if this occurs, loosen shroud mounting base bolts and raise shroud mounting base as required until necessary clearance is obtained. Tighten bolts securely.


SAFETY FEATURES

SAFETY RELATED

Refer to SAFETY page located in front of this, manual and follow all recommended safety warnings.

CHUTE DEFLECTOR AND TRAILING SHIELD

The chute deflector is designed to deflect a thrown object downward. The flexible trailing shield also helps to deflect thrown objects that may exit from under the rear of the mower possibly causing injury to operator or bystander.

Removal of ANY safety related feature will void the warranty. The person removing or altering a safety feature becomes the manufacturer and assumes responsibility should an injury or accident occur.

SAFETY WARNING

WHEN REPLACEMENT PARTS ARE REQUIREDy USE GENUINE OMC PARTS OR PARTS WITH EQUIVA- LENT CHARACTERISTICS INCLUD- ING TYPE, STRENGTHy AND MA- TERIAL. FAILURE TO DO SO MAY

TION AND POSSIBLE INJURY TO THE OPERATOR AND/OR BY- STANDERS.

RESULT IN PRODUCT MALFUNC-

CHECK THE MOWER BEFORE USE

SAFETY WARNING

TO PREVENT ACCIDENTAL STARTING OF MOWER, DISCONNECT SPARK PLUG LEAD BEFORE CHECKING THESE FASTENERS.

Check all nuts, bolts and fasteners for tightness, especially the blade nut (torque blade nut to 50 ft. lbs.). Disconnect spark plug lead before check.

Keep all guards in place at all times.

Keep either cover plate or grass catcher chute with bag in place and secure at all times.

Check grass or leaf bags for wear or deterioration. Re- ;,- place bag if necessary. Use only Lawn-Boy original replacement bags.


-.I___-

SAFETY FEATURES (CONT)

INSTALLING GRASS CATCHER ASSEMBLY O R CHUTE COVER PLATE

SAFETY WARNING

DO NOT OPERATE MOWER WITH- OUT EITHER CHUTE COVER PLATE OR CHUTE AND BAG (WITH ZIPPER CLOSED) LOCKED

TECTION AGAINST OBJECTS BEING THROWN BY THE BLADE THRU

POSURE TO THE ROTATING BLADE.

IN PLACE. THESE PROVIDE PRO-

THE CHUTE OPENING, OR EX-

Both the chute assembly and the cover plate are secure to mower housing in the same manner.

There is a slotted hole in the engine side of chute, and one on inside of chute opening Place the chute (or cover) down into the deck opening s o the two shoulder bolts mounted in the deck protrude thru these holes.

Slide the installed part clockwise with bolt head over slot portion of the two holes

A third hole is located in the end of the installed part . Secure part in place by threading the screw supplied, thru hole in end of part, into mower deck.

2. Chute Installed and Locked in

4. Chute in Locked

5. Chute in Position to be Locked

NOTE

If it is not desired to use the bag and chute, they may be removed and the chute cover placed over housing opening. With engine shut off, and Spark plug lead disconnected, remove the wing screw and slide the chute out of the housing. Install cover in housing opening and secure with wing Screw.

INSTALLING BAG SUPPORT ROD

1. While standing behind the mower, insert lower end of bag support rod thru hole in right handle bracket.

2. Rotate rod until it nests in slot on top of handle bracket. Flange on rod will seat on handle bracket.

1. Rod 2. Flange 3. Mounting Hole 1. Flange 2. Bracket Slot



INSTALLING GRASS CATCHER BAG 1. Insert bottom (wide portion) of bag frame be-

tween the vertical wall of the support shelf and the two retaining lugs at the bottom of the chute opening.

2. Depress' spring latch at top of chute and slip bag frame onto latch. Be certain latch enters hole in bag.

3. Attach the grass bag to the hook at the end of the rod by using one of the three positions provided. Use whichever PO-

pulls the top of the bag TAUT. sition

1. Depress Spring Latch

INSTALLING REAR GRASS BAG ASSEMBLY

FRONT HANGER ASSEMBLY INSTALLATION

1. Remove lock pin from handle pin in left hand handle bracket.

2. Hold front hanger with legs down, horizontal bar across, and the bent leg toward the right.

3. Locate the two open holes in each handle mounting bracket. The outward ends of the front hanger fit into the handle bracket holes.

4. Install front hanger (one side first) into the handle bracket holes. Squeeze in the other side, and snap into the other handle bracket. Oversqueezing will deform the hanger. The short rod ends will project through handle brackets when properly installed.

5. Replace lock pin in left handle bracket pin.

SAFETY WARNING MAKE SURE LOCK PIN IS RE- PLACED AFTER ADJUSTMENT, AND THE LOWER HANDLE CON- TACTS HANDLE UPSTOPS. A LOOSE HANDLE OR IMPROPER FUNCTION OF THE UPSTOP MAY CAUSE LOSS OF O P E R A T O R CONTROL.

9-10

1. Handie Upstop 2. Front Hanger

1. Leg on Right Side

SAFETY WARNING DO NOT USE BAG WITHOUT PLASTIC DEFLECTOR INSTALLED IN BAG SLEEVE. THE DEFLECTOR PROVIDES PROTECTION AGAINST O B J E C T S B E I N G T H R O W N THROUGH THE BAG SLEEVE MA- TERIAL.



INSTALLING GRASS CATCHER BAG NOTE

For easy attachment of the grass bag, follow the assembly steps in sequence.

1. Insert bottom (wide portion) of bag frame between the vertical wall of the support shelf and the two retaining lugs at the bottom of the chute opening.

2. Depress spring latch at top of chute and slip bag frame onto latch. Be certain latch enters hole in bag.

3. Hang front plastic hanger over front hanger bar.

4. Hook rear plastic hanger over r e a r hanger bar.

NOTE

If bag is too tight: 1. Remove rear hanger bar from hanger clips. 2. Loosen bolts. 3. Slide hanger ,clips down to rear notch in hanger 'clip. 4. Reassemble rear hanger bar and tighten wing nuts. 5. Hook rear plastic hanger on bag over hanger bar. If bag fits loosely: 1. Remove r ea r hanger bar from hanger clips. 2. Loosen bolts. 3 . Slide clips rear- ward into the front notch. 4. Reas- semble rear hanger bar, and tighten wing nuts. 5. Hook rear plastic hanger on bag over hanger bar.

For best results when using rear catcher, set engine speed control lever at "NORMAL" position.

SAFETY WARNING To PREVENT INJURIES, ALWAYS

NECT SPARK PLUG WIRE BEFORE CLEANING A CLOGGED CHUTE, BAG TUNNEL, OR MOWER HOUS- ING. DO NOT INSERT HANDS, #TICKS, OR OTHER OBJECTS IN GRASS CHUTE WHILE BLADE IS TURNING.

SHUT OFF ENGINE AND DISCON-

I . Rear Plastic Hanger 2. Sleeve Side of Bag 3. Front Plastic Hanger 4. Chute


BLADE, BLADE HOUSING

UNEVEN CUTTING

Uneven cutting can be attributed to a warped housing, individual wheels not Set at Same cutting height, incorrect blade tracking, bent blade or blade stiffener, or bent crankshaft. Blades out-of-balance can also cause uneven cutting.

Blade cuts high on one side low on other, grass is cut uneven. Warped housings very seldom occur, check all items above.

All four wheels must be at the same height to assure operator of even cut.

INCORRECT BLADE TRACKING

Swirl, arc, or half-moon cuts on smooth level lawns can be caused by the blade being too high, or too low on front or rear area of the housing. Also check UNEVEN CUTTING above. The blade should be tipped down no more than 1/8" from a level position at any place checked.

To check the blade track:

SAFETY WARNING

WHEN SERVICING BLADE, ALWAYS DISCONNECT SPARK PLUG LEAD TO PREVENT A C C I D E N T A L L Y STARTING MOWER.

1. Place the mower on a flat, level surface, making sure all wheels are set at the same height. (The self-propelled mower must have the drive rollers engaging the tires and be in the drive position.)

2. Measure the distance between the level surface and one end of the blade in four 90 degree positions-front, side, rear, side.

Zero to 1/8" low or high from a level condition at front, rear, side "A" and side “B” is acceptable. 3. Shim spacers No. 602913 (.010), NO.

602914 i(.020) or No. 604563 (.025) can be used between the mower housing and muffler! plate to bring the blade back to the proper track. A .025 shim. adjusts the end, of the blade approximately 1/8". The blade stiffener and blade must always be straight and in balance.

Re-tighten' the blade nut to 50 ft. lbs. Re- place blade nut if removed o r installed more than four (4) times.

OF 1/8” UP INSIDE HOUSING FRONT AND REAR AT ALL POINTS EXCEPT FRONT

0 1/8” LOW OR HIGH (OK) SIDE A

A SAFETY REQUIREMENT BEGINNING, 1973 MODEL YEAR. PRIOR TO THIS TIME STANDARD BLADE MUST NOT EXTEND BELOW HOUSING.

FRONT

LOW OR HIGH (OK)

o TO 1/8”

SIDE B

HIGH (OK) o TO 1/8” LOW OR



MOWER BLADES The blade should be checked periodically for the following conditions:

This is a good blade Plenty of lift

A dull blade will cut ragged and deprive the engine of power.

A blade with no lift will not discharge grass won’t cut grass evenly.

Twisted blade will cut very ragged.

ALWAYS REPLACE BLADES THAT ARE QUESTIONABLE. VIBRA- TION FROM AN OUT OF BALANCE BLADE OR BENT STIFFENER CAN CAUSE SEVERE ENGINE DAMAGE AND OPERATOR FATIGUE.

If excess vibration exists with blade & stiffener balanced and knowing engine is not damaged, align blade with the piston, follow steps listed below.

1. Take the spark plug out of the cylinder. 4. File mark the crankshaft end in line with the blade.

2. Loosen the blade, stiffener and adapter on the shaft SO that they turn easily by 5. Mount the blade in direction of file mark hand. thereafter.

3. With the piston at the top of the cylinde.r, 6. Always mount the blade perpendicular to the piston (at a 90° angle).

lbs

NOTE “C” and “D” series engines.

PISTON

DEADCENTER

90° BLADE

I

BLADE’ I


tighten the blade nut to 50 ft.

NOTE: F SERIES ENGINES

Excessive vibration can be reduced by aligning the blade parallel WITH the piston at top dead center.

Turn file mark and blade 90’°

9-13


A blade collar that was damaged and bent when being removed from crankshaft should always be replaced. If not replaced, a vibration in the mower and a rough, uneven or ragged cutting may result.

KEEP BLADE SHARP AND BALANCED

Always keep blade sharp and properly balanced. To check balance, place blade on saw as illustrated. Mounting hole must be centered on saw. If necessary, grind off heavy end of blade until proper balance is attained.

SAFETY WARNING

TO PREVENT POSSIBLE EYE INJURY WHEN GRINDING, ALWAYS WEAR PROPER EYE PROTECTION.

SAFETY WARNING

ALWAYS USE ORIGINAL EQUIP- MENT REPLACEMENT BLADE TO I N S U R E C O M P L I A N C E WITH SAFETY SPECIFICATIONS. WHEN REINSTALLING BLADE, BE SURE PARTS ARE REPLACED IN THE SEQUENCE IN WHICH THEY WERE REMOVED. ALWAYS REPLACE BLADE WITH CURVED EDGE U P (TOWARD HOUSING).

1. Collar 4. Blade 2. Stiffener 5. Nut 3. Washer (20 and 21 inch

models only)


BLADES

1. collar 4. Blade 2. Stiffener 5. Nut 3. Washer (20 and 21 inch

models only)

BBC TRI-CUT BLADE

Until 1983 the blade cutting assembly illustrated here’ was used on Lawn-Boy mowers. A new TRI- CUT blade with a built in stiffener now replaces all blades on 19”. 20” and 21” mowers manufactured in 1959 through 1982. The new TRI-CUT blade eliminates the use of the stiffener and washer. The collar is still required.

ZONE AND P0W.ER RESTART

The 19”, 20” and 21” TRI-CUT Blades are used on zone and power restart models only.

The collar remains on the crankshaft if it is not bent or damaged. The two lugs of the collar locate in the outside holes of the blade to drive it.

BLADE NUT TORQUE IS 45-50 FT. LBS. ON ZONE AND POWER RESTART MODELS.

BBC MODELS ONLY Only one TRI-CUT blade is used on the blade brake, clutch model mowers. The distance between the outside holes is greater and will not fit other models with the collar.

BLADE BOLT TORQUE ON BBC MODELS IS 28-31 FT. LBS.

SERVICE BULLETIN REFERENCES. .9-15 REVISED 1983

,BLADE, BLADE HOUSING

I I

BROKEN OR CRACKED HOUSING

Housing breakage is never covered under warranty except when a definite flaw is found in the metal. However, broken housings can be welded.

NOTE

For welding of the aluminum or magnesium housings, an experienced welder is recommended.

A Heliarc Welder using alternating current (AC) will weld both aluminum and magnesium housings.

NOTE

Do not attempt to weld these housings in the Direct Current (DC) mode.

To Weld Aluminum Housings

Use the Heliarc Welder in AC mode with 40-43 aluminum roil.

To Weld Magnesium Housings

Use the Heliarc Welder in AC mode with pure magnesium rod.

SAFETY WARNING

WELDING MAGNESIUM HOUSINGS WITH AN ACETYLENE TORCH IS NOT RECOMMENDED. A POSSIBIL- ITY OF A FIRE AND/OR AN EXPLO- SION WILL EXIST.

NOTE

All magnesium decks have the word "MAGNESIUM" cast-in place on the left side near "PLACE FOOT HERE WHEN STARTING."

9-16. .SERVICE BULLETIN REFERENCES

CAUSE

TROUBLE SHOOTING BLADE, BLADE HOUSING

Blade dull, nicked, out of balance

Blade bent

Weak blade stiffener

Blade fastener loose

Unequal wheel heights

Mower housing bent or warped

Muffler plate warped/not straight

Bladel/Spacer washer missing (20 & 21” only)

Insufficient engine speed

Insufficient blade tip speed

Cutting wet grass

Grass too long

Rough & uneven turf

Forward travel too fast for cutting conditions

Erratic mowing habits a. Fast and slow movements of

b. Bouncing of handle, etc. mower (jerky operation)

X

X

X

X

X

X

X

X

X X

COMPLAINT

SERVICE BULLETIN REFERENCES.. 9-17

RPM 3487

3400

*3300

*3200

*3100

3000

2900

2800

2700

*2600

*2500

*2400

ROTARY MOWER BLADE TIP SPEED

21” BLADE

Ft. Per Min Miles Per Hour

18,997 215

18,523 210

17,978 204

17,434 198

16,889 191

16,344 185

15,799 179

15,254 173

14,710 167

14,165 160

13,620 154

13,075 148

19” BLADE

Ft. Per Min M.P.H.

17,299 195

16,799 189

16,305 185

15,811 180

15,317 174

14,823 168

14,329 163

13,835 157

13,341 152

12,847 146

12,3 53 140

**11,858 133

18” BLADE

Ft. Per Min M.P.H.

15,844 180

15,378 i75

14,912 168

14,446 164

13,980 159

12,116 138

**11,650 132

**11,184 127

*Minimum & Maximum Speeds Recommended For Operation Of Lawn-Boy Mowers

**NOTE: Blade Tip Speed Below 12,000 F.P.M. Will Not Bag Grass Satisfactorily

SAFETY WARNING: TO MINIMIZE THE HAZARD POTENTIAL OF POSSIBLE FOREIGN, OBJECTS STRUCK BY THE CUTTING BLADE, BLADE TIP SPEED SHOULD NEVER EXCEED 19,000 FEET PER MINUTE FEDERAL SAFETY STANDARDS DOES NOT PERMIT BLADE TIP SPEED TO EXCEED 19ooo FEET PER MINUTE.

9-18 SAFETY RELATED. .SERVICE BULLETIN REFERENCES

SE 'LF-PRO PELLED LOWER BELT DRIVE SERVICING

NOTE

Whenever wheel height o r handle height is changed, clutch control rod and lever must be readjusted. Loosen clamp, lock drive unit in out- of-drive position. Pull up clutch control lever and down on control rod as far as possible and tighten clamp securely.

SAFETY WARNING: IMPROPER TIGHTENING OF

TION COULD RESULT IN LOSING CONTROL OF THE MOWER.

CLUTCH ROD AND LEVER CONNEC-

This adjustment is performed by placing lower end of control rod into groove of clutch control lever assembly. Pull up clutch control lever and down on control rod as far as possible and tighten clamp screw securely. This procedure should provide the required 3/16 inch spacing. However, if it cannot be attained remove right rear wheel and loosen shoulder bolt and adjust axle accordingly. .DRIVE. ROLLER INSTALLATION The drive rollers must be properly installed to utilize the self-cleaning feature. Proper installation is with the vee pointing toward the wheel.


A highriding belt such as this

I

DRIVEN PULLEY

Idler Pin can be bent either way SLIGHTLY to change angle of pulley so V-Belt will ride in center of pulley. Refer to page 10-3. If pulley is cocked either way V-Belt will wear quickly and fail.

DRIVEN IDLER DRIVE

Can result in this


Slide a piece of pipe over idler pulley pin, and bend in the appropriate direction until belt locates in the center of the pulley.

SELF-PROPELLED LOWER BELT DRIVE SERVICING

IDLER PULLEY PIN

Controls Idler Pulley angle. Can be bent either way to make Pulley perpendicular to Belt back. 86" is setting at factory.

TO REMOVE OR CHANGE BELT

Remove Right Roller. Pull Drive Shaft to the left. Remove Belt. Remove Engine from Housing.

SERVICE BULLETIN REFERENCES 10.3


ASSEMBLING SUBBASE TO CRANKCASE

Thoroughly clean sub-base and crankcase mating surfaces, and inspect for nicks o r other damage.

2. Seat sub-base flange in crankcase recess as shown.

3. Twist sub-base until it is properly aligned to crankcase.

4. Insert sub-base to crankcase screws only when properly aligned, and torque them evenly.

5. Lubricate needle bearing through fitting on lower side of sub-base. Use Lawn-Boy “A” grease part no. 610726.

MISALIGNED PULLEY

WILL CAUSE HEAT RUIN the bearing.

VARIABLE DRIVE PULLEY

The sliding half of the pulley must move freely. Use a light FILM of Lawn-Boy “A” grease part no. 610726 on male portion of fixed pulley.

Grease bearing every 25 hours.

MELTED PULLEY

Heat from ruined sub-base bearing did this.

(A stuck sliding half of pulley can cause same results. V-belt will create heat from friction.)


GEAR CLEARANCE-HORIZONTAL

To adjust gear clearance of the driveshaft, loosen the left hand drive roller set screw or remove the drive roller entirely. Pull the driveshaft to the right as far as possible, and hold it there. Insert a .010 feeler gauge between the right hand roller and the nylon bushing and bearing assembly. Hold the drive roller against the feeler gauge and tighten the set screw of the right hand roller, making sure the screw engages the flat on the shaft. Tighten the left hand drive roller set screw, with the drive roller but- ted against the bushing and bearing assembly. This will provide..010 clearance at the bevel gear teeth.


NOTE

Most gear failures result from improper gear mesh which can be prevented by making these two adjustments.

GEAR MESH-VERTICAL

It is very important to closely hold the .180 to .190 clearance between the driveshaft gear and drive gear. Assemble new parts to the mower and measure the clearance by inserting a feeler gauge between bottom of the driveshaft and the top of the teeth in the drivegear. Install shims as required to obtain proper clearance.

SHIMS FOR VERTICAL CLEARANCE

Use .010, ,020, and .025 shims to test. Add o r remove shims to obtain clearance.

.010 Shim Part No. 602913



BUSHING AND BEARING INSTALLATION

When assembling bushing and bearing assemblies, be sure flat side of bushing is up.


SELF- PROPELLED LOWER BELT DRIVE SERVICING

LUBRICATION Hours of Operation

10 hours As Req'd. 10 hours 10 hours 10 hours 10 hours

Lubrication Points

Idler Pulley Bearing Clutch Linkage Driven Pulley Bearing (See Note) Drive Shaft Needle Bearings (See Note) Gears Apply three to four "shots" of grease at

zerk fitting in sub-base beneath housing. Use grease gun.

Lubricant

Light Machine Oil Light Machine Oil Light Machine Oil Lawn-Boy "A" Grease Lawn-Boy "A" Grease

Driven Pulley Bearing: Apply three to four "squirts" of oil at top of pulley bearing.

Drive Shaft Needle Bearings: Unscrew grease plug from end of each drive shaft

roller and apply grease in bearing grease reservoir. Replace plug and tighten until snug, repeat this process until grease appears at points A.

NOTE

Pulley cover must be removed for complete lubrication. To remove, release spring clips and remove cover.


CLUTCH CONTROL ROD ADJUSTMENT Proper control rod adjustment exists when there is 3/16” clearance between the drive rollers and rear wheels with control handle in OUT OF DRIVE position. See Figure 1.

I

TO ADJUST:

1. Place all wheels at same cutting height.

2. Place control handle in OUT OF DRIVE

3. EARLIER MODELS (See Figure 2) position.

Remove spring clip. Remove upper control rod from control handle. Loosen wing nut and locknut from turnbuckle as shown in Figure 3. Turn upper control rod into o r out of turnbuckle until 3/16” dimension (see Figure 1) is achieved with upper control rod reinstalled on control handle in the OUT OF DRIVE position.

FIGURE 3 UPPER

CONTROL ROD

TURNBUCKLE

CONTROL

SELF-PROPELLED UPPER BELT DRIVE SERVICING

3. LATER MODELS (See Figure 4) Loosen wing nut and locknut from turnbuckle as shown in Figure 3. Adjust turnbuckle until the 3/16” dimension is obtained. See Figure 1.

4. Secure turnbuckle with wingnut and locknut.


SELF-PROPELLED SERVICING (UPPER BELT DRIVE)

DRIVE ROLLERS Both drive rollers must engage the mower wheels at the same time, To adjust, loosen top nut and bolt on right side of link and grip assembly and move drive shaft in or out until rollers are equal distance from the wheels. Tighten nut and bolt securely.

LUBRICATION

_-

Drive shaft needle bearings: Unscrew grease plug from end of each drive shaft roller and apply grease in bearing grease reservoir. Replace plug and tighten until grease appears at point A on both bearing assemblies.



NEW BELT INSTALLATION

Remove three screws and remove belt cover.

Slide belt through opening in bracket and under drive shaft. DO NOT twist belt.

Drive the pin from the left drive roller. Remove roller, washer, bearing and bushing assembly.

NOTE The bushing has a flat surface that matches the flat surface of the bracket. When re-assembling, the flat surfaces must match.

I ROLLER I

WASHER BEARING AND PIN BUSHING ]


Seat belt in groove of driveshaft pulley and push belt through opening in shroud DO NOT TWIST BELT.

I 1

Place belt over stationary pulley and around flywheel pulley.

Depress idler pulley and slide belt in place.

CORRECT BELT TENSION Attach belt cover.

To set belt tension: CORRECT BELT INSTALLATION

1. Loosen the bolt holding stationary idler pulley. Using a 12" steel ruler as shown, adjust stationary idler pulley in bracket slot, so that top of pulley is flush to 1/16" below the top surface of flywheel pulley nut. Retighten idler pulley mounting bolt.

2. Position belt on pulleys correctly. SET STATIONARY IDLER PULLEY FLUSH TO 1 /16

WHEEL PULLEY NUT. BELOW TOP OF FLY-

\ I

DRIVE PULLEY 90° TWIST

SPRING LOADED IDLER PULLEY

STATIONARY IDLER PULLEY

DRIVE SHAFT PULLEY

The self-propelled “V” belt is a SPECIAL BELT. Don't use a substitute. It won't work as well o r as long.


SELF=PROPELLED UPPER BELT DRIVE SERVICING

BELT ALIGNMENT

ALIGNMENT PROCEDURE

See NOTE" NE X T PAGE REGARDING OLDER MOWERS.

1. Remove spark plug lead. Place control handle in Out-of-Drive position.

2. Set belt tension. Refer to page 10-10.

3. Examine driven pulley. If only one set screw is found and pulley cannot be secured properly, replace with double set screw driven pulley #679411.

4. Hold driveshaft so that all of the end play appears on the right side as shown in illustration. If excessive end play exists, refer to page 10-12 for correction.

5. Using a 12" steel rule, adjust the lower driven

118-5132" FROM MACHINED SURFACE OF LOWER DRIVEN PULLEY (INSIDE EDGE OF THE 12" STEEL RULER) TO THE POINT WHERE THE BELT ENTERS THE GROOVE ON THE SPRING LOADED IDLER PULLEY \

pulley so that the machined surface on the left side of the pulley is 1/8" 5/32" from the edge of the belt ( NOTE: See note on next page for early model upper belt drive self-propelled mowers) at the point where the belt enters the groove on the spring loaded idler pulley. Tighten set screws on lower driven pulley securely.

6. Put mower IN-GEAR, raise handle to highest position. Maintain a minimum of 3/32" clearance between belt and tank flange. Also, check for adequate clearance between movable idler pulley and top of tank. If necessary, .loosen fuel tank mounting brackets and slide tank away from belt and/or pulley. Retighten bracket.


NOTE:

EARLY PRODUCTION MOWERS

The alignment procedure for early production upper belt drive self-propelled mowers specifies a measurement of 15/32" from machined surface of lower driven pulley to the point where the belt enters the groove on the spring loaded idler pulley.

THIS BRACKET USED ON EARLY PRODUCTION MOWERS

FIGURE 1 OLD STYLE BRACKET

SMALL HALF MOON

NO REINFO~EMENT RIB IF MOWER HAS OLD STYLE BRACKET USE 15/32" MEASUREMENT 94336

15/32" FROM MACHINED SURFACE OF LOWER DRIVEN PULLEY IlNSlDE EDGE OF THE 12 ' STEEL RULER) TO THE POINT WHERE THE BELT

THE SPRING LOADED IDLER ENTERS THE GROOVE ON

PULLEY

SPRING LOADED IDLER PULLEY

To determine early production mowers observe the bracket that mounts the stationary and movable idler pulleys. See Figures 1 and 2.

THIS BRACKET USED ON LATER PRODUCTION MOWERS

FIGURE 2 NEW STYLE FORMED BRACKET

CORNERS LARGE HALF

MOON

RE~NFORC~MENT RIB IF MOWER HAS NEW STYLE BRACKET USE 1/8" TO 5/32" MEASUREMENT 94336

FOR IDLER BRACKET AND PULLEY ASSEMBLY REPLACEMENT

USE PART NO. 681075 FOR ALL TOP BELT DRIVE MODELS

DRIVESHAFT END PLAY

There should only be sufficient end play in the driveshaft to allow the clutch assembly to pivot freely. To eliminate excessive end play proceed as follows: Applies particularly to 1968-1969 models.

1. Remove the shoulder bolt and wave washers. See Illustration.

2. Reinstall shoulder bolt using sufficient spacers (plain or solid washers) until .012-.015 end play is obtained; o r install replacement shoulder bolt P/N 606672. It is not necessary to replace wave washers removed in step 1.

3. Re-check belt for proper alignment.


SERVICE CHECK LIST FOR UPPER BELT DRIVE SELF PROPELLED MOWERS

1. Check all parts on drive system. Replace any part that is worn, cracked or broken.

2. Spring-loaded idler arm must operate freely to follow engagement and disen- gagement.

3. Grommet no. 311915 must be intact and without wear. Sand and other abrasive material will shorten its life substan- tially.

4. Check pulleys for wear, cracks or damage in “v” groove. Replace if necessary.

5. Belt must be free of oil and grease.

6. Make sure clutch control rod is properly adjusted for smooth operation. Check that brackets are secure on deck.

7. Check drive rollers for equal engagement to rear wheels. Three-sixteenths inch clearance recommended with drive disengaged. Is driveshaft bowed?

8. Check end-play on driveshaft. See page 10-12 paragraph 2. Use spacer washers if needed. This applies especially to early production models; i.e. 1968-1969.

9. Align lower driven pulley. Tighten set screws. Keep pulley well in deck clean. If necessary,

install new drive pulley Part No. 679411 which includes 2 set screws.

10. Check belt shield to shroud. If it inter- feres with belt, bend slightly to eliminate belt contact. Check belt cover for pulley interference.

11. Pulley bracket. Make sure the correct bracket and pulley assembly is installed. Models up to and including 8229 and 8229E use replacement Part No. 678772. Models from 8229A, 8229B, 8229C, 8229D, 8229F and 8229EA use replacement Part No. 681075.

12. Correct tracking of belt from lower driven pulley to stationary idler pulley and idler pulley to upper drive pulley nut.

13. Belt and belt tension: Replace worn o r thrown belt (could be cracked or stretched).

14. Lubrication: Lube driveshaft bearings. Drive bearings may wear shaft and cock lower drive pulley.

15. Vibration: Excessive vibration may throw loose belt. Reduce vibration by balancing blade and blade stiffener. Re- install blade at 90° to piston with piston at top dead center.

16. If belt appears too long, check length. Correct length should be 35-1/2 inches

1/16 inch.

17. If all above points are correct, check operator and educate on correct operation. The cause may be twigs, pine needles, bushes, etc., getting into the drive system and throwing belt. Also, educate customer on proper clutching. Slip clutching, etc., can result in belt throwing.

18. If shrub or tree branches are causing belt to jump from flywheel nut pulley, a new improved belt cover, Part NO. 681010, may be installed to prevent this.

SERVICE BULLETIN REFERENCES REVISED1977 10-13

D-600 SERIES GEAR DRIVE SELF-PROPELLED

GROUND SPEED SELECTION. Combinations of the various drive roller sizes and transmission gear ratios are available to change the ground speed.

Refer to the following specifications and information to obtain the desired ground speed.

Drive Rollers .88” Dia. L.H. Drive Roller 607657 .88” Dia. 607658 R.H. Drive Roller

1.00” Dia. 610844 L.H. Drive Roller 1.00” Dia. 610845 R.H. Driver Roller

1.12” Dia. 610440 L.H. Drive Roller 1.12” Dia. 610441 R.H. Drive Roller

Transmissions

15 Tooth 607663 Gear Drive 15 Tooth 607664 Gear Driven

16 Tooth 610687 Gear Driven 14 Tooth 610688 Gear Drive

Ratio Driver Roller 3200 RPM 15:15 .88 3200 RPM 14:16 .88 3200 RPM 14:16 1 .OO 3200 RPM 14:16 1.12

Speed MPH 2.7 2.4 2.8 3.1

14:16 Gear ratio transmission will fit all 679699 (metal) and plastic gear cases. NOTE:

To change ground speed on mowers manufactured prior to 1980, it would be necessary to replace the axle bracket part number 608934 with part number 610500 bracket. This includes all D-600 series, 1978 and 1979 “F’ series.

NOTE:

Do not use the 1.00’’ and 1.12” diameter drive rollers with a 15:15 ratio transmission. Ground speed would be excessive with poor cutting results.

D-600 SERIES GEAR DRIVE SELF PROPELLED SERVICING

CLUTCH ADJUSTMENT The clutch control rod and lever must be adjusted to provide a 3/16 inch space between the drive rollers and rear wheels.

SAFETY WARNING: I M P R O P E R T I G H T E N I N G OF CLUTCH ROD AND LEVER CON- NECTION MAY RESULT IN OPER- ATOR LOSS OF DRIVE CONTROL MECHANISM.

Place mower in "OUT-OF-DRIVE" position, Adjustment is performed by placing lower end of control rod into groove of clutch control lever assembly. Pull up clutch control lever and down on control rod as far as possible and tighten clamp screw securely. This procedure should provide the required 3/16 inch spacing. However, if it cannot be attained, remove right rear wheel and loosen shoulder bolt and adjust axle accordingly.

I I

Whenever NOTE

wheel height o r handle height is changed, clutch control rod and lever must be readjusted. Loosen clamp, lock drive unit in out- of-drive position. Pull up clutch control lever and down on control rod as far as possible and tighten clamp securely.


REPAIR OR REPLACE GEARS, SHAFT, THRUST WASHER AND/ OR SEAL

NOTE

Remove spark plug lead. On electric start models disconnect and remove battery.

1. Remove transmission gear cover. 2. Remove blade, blade stiffener, and adapter. 3. Remove muffler (4 nuts). 4. Remove transmission mounting screw from

underside of deck as shown. 5. Remove nuts from three engine mounting bolts. 6. Remove engine from mower housing.

NOTE

Do not remove stub drive shaft (P.T.O.) from crankcase.

7. Remove four screws securing gear cover to crankcase.

8. Remove P.T.0 shaft. Sharp spline edges may cut seal. Replace seal. To replace seal, remove by inserting screwdriver under one side and prying up. Seal may be reinstalled by placing squarely in seal opening and driving in with a 5 / 8 inch socket and soft headed (leather or plastic) hammer.

NOTE

P.T.O. shaft should be installed in crankcase before seal is installed to safeguard against damage to seal.

NOTE

Early production model crankcase contains loose thrust washer part number 608363 to provide bearing surface for downward thrust of crankshaft. When reinstalling, locate hole in thrust washer over stationary pin in crankcase. Later production models will have thrust washer cast in crankcase.


D-600 SERtES GEAR DRIVE SELF PROPELLED SERVICING

DRIVE TUBE END PLAY

1. Using a feeler gauge check for excessive end play as shown. If end play measurement is .035 to .135, no “0” ring is required. If measurement is .136 to .235, add one “0” ring to transmission drive shaft as shown. If measurement is .236 or higher, add one “0” ring to transmission drive shaft and one “0” ring to engine drive shaft as shown. Replacement part no. for “0” ring is 303067.

2. Check position of bushings in drive tube. They must be installed with chamfered end inserted in drive tube as illustrated. Always replace. worn bushings.

3. A sintered metal bushing must always be installed in end next to engine.

REPAIR OR REPLACE TRANSMISSION 1. Remove transmission gear cover. 2. Remove blade, blade stiffener, and adapter. 3. Remove muffler (4 nuts). 4. Remove transmission mounting screw from

5. Remove nuts from three engine mounting bolts. 6. Remove engine from mower housing carefully

to avoid pulling driven shaft from lower drive unit.

underside of deck.

NOTE

If drive shaft is removed from crankcase, the drive gear will drop off end of shaft. If shaft is removed, it will be necessary to remove gear cover, replace the seal, cover gasket and reassemble gear and shaft.

NOTE If a failure of the drive tube or bushings occurs on any gear driven self-propelled mower, it is to be replaced with the new spring loaded assembly shown here. Also remove and discard all “0” rings used with the old tube. Refer to the parts book and master parts price list for the part numbers.



7. Remove both drive rollers. Slide bearing and bushing assemblies off each end of shaft.

NOTE

When reinstalling drive rollers place one washer between bearing and bushing assemblies and drive roller on each end. This will provide correct end play of .062 inch or less. If end play exceeds this, install additional washer, part no. 603037, between right bushing and bearing and drive roller.

NOTE

The bushing has a flat surface that matches the flat surface of the bracket. When re-assembling, flat surfaces must match.

8. Remove two “C” clamps securing top and bottom gear covers.

9. Remove drive shaft and transmission assembly complete.

10. Drive roll pin out of bevel gear and drive shaft, and slide shaft out of bearing housing.

NOTE

Replace gears in sets. Do not replace individually.

11. To replace bearing, press out damaged o r worn bearing with special Lawn- Boy removal tool, part number 608361, and press in replacement with special installer tool, part number 608360.

Do not drive bearings in or out with hammer. They must be removed and replaced using arbor press as illustrated.

e

HARDENED SURFACE



NOTE

In servicing the drive shaft, there is one very important consideration; there is a left and a right-hand side. The reason for this is that the bearing surface side (left of center) is hardened to prevent wear.

When facing the rear of the mower (operator’s position), measure the distance from end of shaft to the first hole. A measurement of 1-1/32” inch is the left end. The other end will measure 1-5/16” inch to the first hole as illustrated.

pin hole to the end of the shaft. As illustrated, the measurement on the left- hand side is 1-1/32 inch as opposed to 15/16 inch on the right-hand side.

LEFT SURFACE RIGHT

LUBRICATION

DRIVE GEAR BEARINGS- Remove cover on rear of mower housing (secured by two screws). Remove inner top cover to expose gears (secured by two clamps). Apply grease through each zerk fitting until grease appears at the inside end of bracket. USE LAWN-BOY “A” GREASE.

DRIVE GEARS-Wipe a liberal amount of lubricant on all surfaces of teeth on both gears. USE LAWN- BOY “A” GREASE.

DRIVE ROLLER BEARINGS- Unscrew plug from end of each drive roller. Fill exposed cavity with LAWN-BOY “A” GREASE. Re- place plug and tighten until snug. Repeat procedure until lubricant appears on drive shaft a t Point A.

TOP COVER REMOVED FOR ILLUSTRA- TION

BLY. SERVICE BULLETIN REFERENCES REVISED 1977 10-19

“F” SERIES GEAR DRIVE SELF-PROPELLED

GROUND SPEED SELECTION

Combinations of the various drive roller sizes and transmission gear ratios are available to change the ground speed.

Refer to the following specifications and information to obtain the desired ground speed.

Drive Rollers .88” Dia. 607657 L.H. Drive Roller .88” Dia. 607658 R.H. Drive Roller

1.00” Dia. 610844 L.H. Drive Roller 1.00” Dia. 610845 R.H. Drive Roller 1.12” Dia. 610440 L.H. Drive Roller 1.12” Dia. 610441 R.H. Drive Roller

Transmissions 15 Tooth 607663 Gear Drive 15 Tooth 607664 Gear Driven

16 Tooth 610687 Gear Driven 14 Tooth 610688 Gear Drive

Ratio Drive Roller Speed MPH 3200 RPM 15:15 .88 2.7 3200 RPM 14:16 .88 2.4 3200 RPM 14:16 1.00 2.8 3200 RPM 14:16 1.12 3.1

14:16 Gear ratio transmission will fit all 679699 (metal) and plastic gear cases.

NOTE

To change ground speed on mowers manufactured prior to 1980, it would be necessary to replace the axle bracket part number 608934 with part number 610500 bracket. This includes all D-600 series, 1978 and 1979 “F” series.

NOTE

.

Do not use the 1.00” and 1.12” diameter drive rollers with a 15:15 ratio transmission. Ground speed would be excessive with poor cutting results.

10-20 ..SERVICE BULLETIN REFERENCE

“F” SERIES GEAR DRIVE SELF PROPELLED SERVlClNG CLUTCH ADJUSTMENT

The clutch control rod must be adjusted to provide a 3/16 inch space between the drive rollers and rear wheels.

Place mower in “OUT-OF-DRIVE” position, Adjustment is performed by placing lower end of control rod into groove of clutch control lever assembly. Pull up clutch control lever and down on control rod as far as possible and tighten clamp screw securely. This procedure should provide the required 3/16 inch spacing. However, if it cannot be attained, remove right rear wheel and loosen shoulder bolt and adjust axle accordingly.

SAFETY WARNING I M P R O P E R T I G H T E N I N G O F CLUTCH ROD AND LEVER CON- NECTION MAY RESULT IN OPERA- TOR LOSS OF DRIVE CONTROL MECHANISM.

Whenever wheel height o r handle height is changed, clutch control rod and lever must be readjusted. Loosen clamp, lock drive unit in out- of-drive position. Pull up clutch control lever and down on control rod as far as possible and tighten clamp securely


“F” SERIES GEAR DRIVE SELF PROPELLED SERVICING

DRlVE ROLLER INSTALLATION

The drive rollers must be properly installed to utilize the self-cleaning feature. Proper installation is with the vee pointing toward the wheel.

Always replace the roll pin with a new one. Drive it into place with 5/32” or larger drift punch. Neither end of pin should protrude beyond surface of roller.

STARTER INTERLOCK-SELF PROPELLED MODELS

The starter interlock is a safety feature on self-propelled models. This system prevents starting the engine when the control handle is in the “DRIVE” position. The interlock cable is attached to the rear axle and an interlock lever. When the control handle is placed in “DRIVE” position the cable rotates the interlock lever upwards into a position

that prevents the starter pinion from engaging the flywheel. When the control handle is placed in “NEUTRAL” position the interlock cable pulls the interlock lever downward, allowing the starter pinion to engage flywheel as shown. This permits starting the engine with the control handle in the “NEUTRAL position only.


"F" SERIES GEAR DRIVE SELF PROPELLED SERVICING A SAFETY WARNING

INTERLOCK OPERATING SPRING MUST BE IN PLACE ON BOTH THE ELECTRIC AND MANUAL START MODELS TO PREVENT STARTING OF ENGINE WHILE IN DRIVE POSITION.

NOTE

Do not replace spring with other than original equipment to assure correct operation.

INTERLOCK SPRING P/N 302993

INTERLOCK

CABLE CLIP "NEUTRAL"

INTERLOCK SPRING I

609571 CLIP CABLE

Misadjustment of the interlock system will eliminate the safety feature it was designed for and may permit starting the engine with control handle in "DRIVE" position causing possible injury to operator.

Proper adjustment is accomplished as follows:

1. Place control handle in "NEUTRAL" position. Adjust clutch control rod by loosening clamp and pulling up on lower lower clutch lever and down, on upper clutch rod until a gap of 3/16" appears between the drive rollers and the rear wheels. Tighten clamp as tight as possible with hand pressure.


“F” SERIES GEAR DRIVE SELF PROPELLED SERVICING This procedure should provide the required 3/16 inch spacing. However, if it cannot be attained, remove right rear wheel and loosen shoulder bolt and adjust axle accordingly.

NOTE

Check felt wheel washers and replace if necessary. Do not lubricate wheel and axle assembly.

3. MANUAL START MODELS: Place control handle in “NEUTRAL” position. Observe movement of interlock lever. The lever should be in a position that allows the starter pinion to engage the flywheel when the starter handle is in neutral. To adjust: remove spring clip and position interlock cable until a clearance of .090” is obtained between starter pinion and interlock lever as shown to allow necessary movement of starter pinion. Hold interlock cable in position, DO NOT allow cable to move, and secure interlock cable to starter bracket with spring clip as shown with a pair of pliers.

SAFETY WARNING I M P R O P E R T I G H T E N I N G OF CLUTCH ROD AND LEVER CON- NECTION MAY RESULT IN OPERA- TOR LOSS OF DRIVE CONTROL MECHANISM.

Remove left drive roller guard and left rear wheel. Loosen cable retainer clip and position end of cable housing (with rubber grommet installed on cable) 1-1/2 inches from nearest edge of retainer clip as shown. Secure clip and reinstall drive roller guard and wheel.

NOTE If .090” measurement between starter pinion and interlock lever can not be obtained using procedure #3 above then remove cable clip from rear axle bracket and position cable until .090” clearance is obtained. Secure cable to rear axle bracket and clip with pliers.


"F" SERIES GEAR ELECTRIC START MODELS: Place control handle in "NEUTRAL" position. Observe movement of interlock lever when manual starter handle is pulled and when key is turned to "START" position. The interlock lever should be in a position that allows the starter pinion to engage the flywheel. To adjust; remove spring clip and position interlock cable to allow necessary movement of starter pinion. Hold interlock cable in position, DO NOT allow cable to move, and secure interlock cable with spring clip with a pair of pliers.

NOTE

If necessary clearance can not be obtained by using above procedure then remove cable clip from rear cable clip from rear axle bracket and position cable until clearance is obtained. Secure cable to rear axle bracket with clip.

Place control handle in "DRIVE"position. Observe movement of interlock lever. When properly adjusted interlock lever will move upward preventing starter pinion from engaging flywheel. To adjust; remove spring clip and position cable so interlock lever prevents starter pinion from engaging flywheel. Secure cable with spring clip.

DRIVE SELF PROPELLED SERVlClNG 5.

6.

Check movement of interlock lever in "NEUTRAL" and "DRIVE" position. Check to be certain mower will start with control handle locked in "NEUTRAL" position ONLY. Mower should NOT start with control handle locked in "DRIVE" position. If additional adjustment is required repeat steps 3 & 4.

A I SAFETY WARNING

Check interlock operation whenever drive roller engagement or- rear axle adjustment is changed. It is NOT necessary to check interlock adjustment when cutting height or handle height has been changed. Clutch control rod will require adjustment when handle or cutting height is changed.

To replace interlock cable; remove left side drive roller cover and rear wheel. Remove spring clip securing the cable to the deck and remove cable from rear axle. The interlock lever is designed with a "quick disconnect" feature that allows the cable to be easily removed. Remove spring clip securing cable to starter bracket. Rotate cable approximately 45° counterclockwise and remove cable from interlock lever as shown. Reverse procedure when installing new cable. The washer located on the end of the cable must be installed next to the cable loop to secure cable tointerlock lever. DO NOT lubricate interlock cable if cable movement is restricted or cable damaged replace cable. For adjusting procedure follow steps 1, 2 and 3.



To remove the rear wheels remove retainer ring with expansion pliers # 603596.

SAFETY WARNING

DO NOT OVER EXTEND (STRESS) RETAINING RING WHILE REMOV- ING OR INSTALLING. WHEN IN- STALLING RETAINING RING PO- SITION THE SIDE WITH THE ROUND OR BEVELED EDGES IN TOWARDS THE WHEEL. MAKE CERTAIN RETAINING RING IS NESTED IN GROOVE OF AXLE. LOSS OF WHEEL MAY ALLOW BLADE TO CONTACT GROUND SURFACE AND PICK UP OBJECTS THAT MAY BE THROWN BY THE BLADE.

The rear wheels are adjusted with one lever at the rear of mower deck.

SAFETY WARNING

MAKE SURE COTTER PIN AND ALL

PONENTS ARE IN PLACE. LOSS OF COTTER PIN MAY CAUSE REAR OF MOWER TO DROP PERMITTING BLADE TO PICK UP OBJECTS THAT MAY BE THROWN.

REAR HEIGHT ADJUSTMENT COM-


“F” SERIES GEAR DRIVE SELF PROPELLED SERVICING REPAIR OR REPLACE DRIVEN GEAR, SHAFT, THRUST WASHER AND/OR SEAL

Remove spark plug lead. Electric start models remove battery and disconnect starter lead wires.

1. Remove blade, blade stiffener, and adapter.

2. Remove muffler.

3. Remove transmission mounting screw from underside of deck as shown.

4. Remove engine mounting fasteners.

When reinstalling transmission mounting screw torque to 70 inch pounds.

5. Remove drive shaft cover.

SAFETY WARNING

DRIVE SHAFT COVER AND ROLLER GUARDS MUST BE IN PLACE A T

TOR EXPOSURE TO ROTATING PARTS.

ALL TIMES TO PREVENT OPERA-

6. Remove engine from mower housing.

Do not remove shaft from crankcase gear housing.

7. Loosen four screws securing gear cover assembly to crankcase. DO NOT remove the four screws a t this time.



8. Carefully remove driveshaft from gear box assembly. Sharp spline edges will cut seal. Al- ways replace seal. To replace seal, remove by inserting screwdriver under one side and prying up. Seal may be reinstalled by placing squarely on seal seat and tamping in by using 5/8 inch socket and soft headed (leather or plastic) hammer.

10-28

NOTE

Driven shaft should be installed in lower unit before seal is installed to safeguard against damage to seal.

Remove four screws and remove gear cover assembly from engine. Remove bronze gear and thrust washer. Inspect for wear and/or damage. Also inspect spiral gear of crankshaft for wear and damage. Replace any part that is questionable.


"F" SERIES GEAR DRIVE SELF PROPELLED SERVICING

DRIVE TUBE END PLAY

1. Using a feeler gauge check for excessive end play as shown. If end play measurement is .035 to .135, no "0" ring required. If measurement is .136 to .235, add one "0" ring to transmission driver gearshaft as shown. If measurement is .236 or higher, add one "0" ring to transmission driven gearshaft and one "0" ring to engine driveshaft as shown. Replacement part no. for "0" ring is 303067.

2. Check position of bushings in drive tube. They must be installed with chamfered end inserted in drive tube as illustrated. Always replace worn bushings.

3. A sintered metal bushing must be installed on end next to engine.

CHAMFERED END OF BUSHING

DRIVE TUBE

REPAIR OR REPLACE TRANSMISSION

1. Remove transmission cover plate and drive

2. Remove blade, blade stiffener, and adapter. 3. Remove muffler. 4. Remove transmission mounting screw from

5. Remove engine mounting bolts.

roller covers.

underside of deck.

NOTE If a failure of the drive tube or bushings occurs on any gear driven self-propelled mower, it is to be replaced with the new spring loaded assembly shown here. Also remove and discard all "0" rings used with the old tube. Refer to the parts book and master parts price list for the part numbers.



6. Remove engine from mower housing carefully to avoid pulling P.T.O. shaft from lower crankcase gear housing.

NOTE

If P.T.O. shaft is removed, the driven gear will drop off end of shaft. Refer to steps 6 thru 9, REPAIR OR REPLACE DRIVEN GEAR, SHAFT, THRUST WASHER AND/OR SEAL.

7. Remove drive rollers and drive shaft roller bearings.

NOTE When reinstalling drive rollers place one washer between roller bearing and drive roller on both sides. This will provide correct end play of .062 inch or less. If end play exceeds this, install additional washer, part no. 603037, between right roller bearing and drive roller.

NOTE The sleeve has a flat surface that matches the flat surface of the bracket. When re-assembling, flat surfaces must match.

8. Remove two “C” clamps securing top and bottom gear covers.

9. Remove drive shaft and transmission assembly complete.

10. Drive roll pin out of bevel gear and drive shaft, and slide shaft out of bearing housing.

NOTE

Replace gears in sets. Do not replace individually.


"F" SERIES GEAR DRIVE SELF PROPELLED SERVICING

11. To replace bearing, press out damaged or worn bearing with special Lawn- Boy removal tool, part number 608361, and press in replacement with special installer tool, part number 608360.

Do not drive bearings in or out with a hammer. They must be removed or replaced using arbor press as illustrated.

LEFT SURFACE RIGHT

REMOVAL INSTALLATION TOOL TOOL

NOTE

In servicing the drive shaft, there is one very important consideration; there is a left and a right-hand side. The reason for this is that the bearing surface side (left of center) is hardened to prevent wear.

When facing the rear of the mower (operator's position) measure the distance from end of shaft to the first hole. A measurement of 1-1/32 inch is the left end. The other end will measure 1-5/16 inch to the first hole as illustrated.


“F” SERIES GEAR DRIVE SELF PROPELLED SERVICING LUBRICATION

25 Hours

1.

2.

3.

DRIVE GEAR BEARINGS-Remove cross- shaft cover on rear of mower housing (secured by two screws). Remove inner top cover to expose gears (secured by two clamps). Apply grease through each grease fitting until grease appears a t point “A.” USE LAWN-BOY “A” GREASE.

DRIVE GEARS-Apply a liberal amount of lubricant on all surfaces of teeth on both gears a t point “B.” USE LAWN-BOY “A” GREASE.

DRIVE ROLLER BEARINGS-Unscrew plug from end of each drive roller. Fill exposed cavity with LAWN-BOY “A” GREASE. Replace plug and tighten until snug. Point “C.” Repeat procedure until lubricant appears on cross- shaft a t Point “D.”

NOTE

Do not lubricate the wheels or axle bolts. The lubricant can accumulate dirt and debris accelerating wear.

AS REQUIRED

4. CLUTCH LINKAGE-Apply several drops of light machine oil on clutch at Point “E” as shown.

TOP COVER REMOVED FOR ILLUSTRA- TION


UTILITY MODELS SELF-PROPELLED BELT DRIVE

SERVICING Adjustments and servicing of the utility self- propelled mowers are very different from all previous models of self-propelled mowers.

SAFETY WARNING

BEFORE ANY ADJUSTMENTS OR

CONNECT AND REMOVE SPARK PLUG TO PREVENT STARTING.

REPAIRS ARE ATTEMPTED, DIS-

95064

INSTALLING CONTROL ROD

1. Place retainer clip on clutch arm with long side of clip on the inside of clutch arm.

2. Align hole in clip with hole in arm and assemble lower end of the control rod in hole.

3. Turn (swivel) long end of clip up and snap into position on lower control rod as shown.

THE LOWER SELF PROPEL CON- TROL ROD MUST BE ASSEMBLED TO CLUTCH ARM AS SHOWN. I F NOT THE SELF PROPEL MECH- ANISM WILL NOT RETURN TO NEUTRAL WHEN THE CONTROL LEVER IS RELEASED FROM THE ENGAGED POSITION.


UTILITY MODELS

SERVICING SELF-PROPELLED BELT DRIVE

4. With the control handle in "neutral" (free) position a s shown.

5. With the clutch arm resting on the handle and wheel bracket as shown.

10-34

6. Secure upper and lower control rods together with the clamp screw as shown. This screw should be tightened securely by hand.

SAFETY WARNING

IMPROPER TIGHTENING OF CLAMP SCREW ON CONTROL ROD MAY RESULT IN OPERATOR LOSS OF DRIVE CONTROL MECHANISM.

To put mower in motion, pull upward on control handle and hold in drive position. To stop forward motion of mower, release control handle. Mower drive mechanism functions only when the control handle is held in "DRIVE" position.


DRIVE ROLLER ADJUSTMENT

1. With the control handle in "Neutral", place both rear wheel height adjusters in #1 (lowest) cutting position as shown. A gap of 3/16" should appear between the drive rollers and tires.

2. Loosen bolt and nut located in drive roller gap adjusting slot on each side of drive roller bracket.

3. Move the drive roller bracket up o r down to obtain the necessary 3/16'' drive roller gap. Hold bracket in position and tighten both bolts and nuts securely.

UTILITY MODELS


ENGINE REMOVAL OR REPLACEMENT

SAFETY WARNING

TO PREVENT STARTING OF EN- GINE, DISCONNECT AND REMOVE SPARK PLUG PRIOR TO REMOVING THE ENGINE.

1. Remove blade bolt, washer, blade stiffener, collar and three bolts securing muffler and remove muffler.

2. Remove three bolts securing engine to muffler plate and remove engine.

Do not remove muffler plate from housing when removing engine.


UTILITY MODELS


V BELT REMOVAL OR REPLACEMENT

SAFETY WARNING

TO PREVENT STARTING ENGINE, DISCONNECT SPARK PLUG LEAD AND REMOVE SPARK PLUG.

The "V" belt used on the utility self- propelled model mowers is a SPECIAL BELT. DO NOT USE A SUBSTITUTE. It won't work a s WELL o r a s LONG.

To remove the belt:

1. Remove four belt guard cover screws and remove cover.

2. Remove engine and remove drive belt from drive pulley.

SAFETY WARNING

DO NOT OPERATE MOWER WITH BELT GUARD REMOVED.

3. Remove roll pin from left hand drive roller and remove roller.

4. Remove belt from driven pulley and slide shaft assembly to the right. Remove belt from mower as shown.


After the belt has been removed, examine for broken, cracked or misaligned pulleys. The condition and the wear pattern of the belt will provide clues for the above possibilities. Replace damaged o r worn pulleys.

5. The crankshaft pulley (drive pulley) is secured to the crankshaft with a SPECIAL slotted set screw. The end of this screw locates in a hole in the crankshaft. The correct position and tightness is very IMPORTANT. If not tightened securely, damage to the pulley, crankshaft and premature wear of the drive belt will result.

Apply OMC Ultra Lock part no. 388517 to threads of set screw prior to installation.

UTILITY MODELS


6. When reinstalling pulley to crankshaft, the side of the pulley with s e t screw is the lower side. If assembled upside down (set screw on top) misalignment and interference of pulley operation will result. Always check pulley for damage-. Replace if necessary.

UTILITY MODELS


IDLER SAFETY WARNING PULLEYS TOP STRAND

INCORRECT DRIVE BELT INSTAL LATION MAY ALLOW MOWER TO OPERATE IN REVERSE DIRECTION

TOR OR BYSTANDERS. ASSEMBLE DRIVE BELT AS SHOWN.

CAUSING INJURY TO THE OPERA-

DRIVE- BOTTOM STRAND ENGINE SHAFT DRIVE PULLEY PULLEY

INSTALL BELT AS SHOWN FOR PROPER PULLEY ROTATION

8. Check the condition of the driveshaft, bronze bearings, and sleeve. If signs of damage or wear appear, replace them.

7. Place belt over left end of drive shaft 'as shown. Do not assemble on driveshaft pulley.

9. BUSHING AND BEARING INSTALLA- TIONS.

NOTE

The sleeve has a flat surface that matches the flat surface of the bracket. When reassembling, the flat surfaces must match.


10. Reassemble the drive shaft into the bearing and slide it to the left as far as possible. Assemble the washer and drive roller on the drive shaft.

11. The drive rollers must be properly installed to utilize the self-cleaning feature. Proper installation is with the vee pointing toward the wheel.

12. Using a new roll pin, assemble the drive roller to the drive shaft. Use a 5/32” or larger drift punch, drive the roll pin into place, flush with the outer surface. Neither end should protrude beyond the roller surface.

UTILITY MODELS



13. As you face the front of the mower, twist the forward end of the belt 1/4 turn counter clockwise and assemble on the engine drive pulley. Assemble engine on muffler plate and secure with three bolts.

14. Release spring tension on idler pulleys and assemble belt on drive shaft pulley. Reassemble idler pulley spring and rotate the belt several revolutions. Check to make sure the belt is centered on the pulleys and TURNING IN RIGHT DIREC- TION. Note direction of arrow on large pulley in illustration above. Check and adjust belt tension if necessary. Refer to BELT TENSION ADJUSTMENT.


NOTE When replacing either of the belt idler assemblies, use idler kit part no. 682374 for the top and kit part no. 682564 on the bottom.

10-39

UTILITY MODELS


BELT TENSION ADJUSTMENT

1. Check drive belt installation. Drive belt must be installed between idler pulleys as shown.

2. Drive belt should be checked to insure that proper tension exists in order to prevent premature belt failure. Lift floating idler from the upper strand of "V" belt. Belt will then become loose. Set floating idler onto "V" belt and check clearance between the two strands of the "V" belt. ,The distance between the two strands should not be less than 1/2" a s shown.

3 . To adjust belt tension; loosen four handle bracket mounting screws (two on each bracket) and two screws (one on each side) located on the sides of rear height adjuster bracket as shown. Slide entire self-propelling mechanism in direction necessary to obtain the proper "V" belt tension.

4. Care should be taken to insure that both sides of the self-propelling mechanism a r e positioned equally on the mower housing. This can be accomplished by measuring the distance from the front edge on the height adjuster brackets to the 1/4" diameter gage holes located directly in front of these brackets as shown. This distance must be the same for both sides. Before tightening screws make sure the distance between the strands of the "V" belt is not less than 1/2". Tighten the four handle bracket screws and the two side screws securely. Reassemble belt guard to- self-propel mechanism using screws previously removed.

SAFETY WARNING DO NOT OPERATE MOWER WITH BELT GUARD REMOVED.


LUBRICATION

10 HOURS

1. DRIVE ROLLER BEARINGS-Disassemble rotating shaft cover from self-propel mechanism by removing four screws. Unscrew plug from end of each drive roller (Point “A”). Fill exposed cavity

610721 OR EQUIVALENT. Replace plug and tighten until snug. Repeat procedure until lubricant appears on cross-shaft at Point “B”. Reas- semble rotating shaft cover to self-propel assembly.

with LAWN-BOY “A” GREASE, PART NO.

UTILITY MODELS


OLD STYLE LOWER IDLER ASSEMBLY

FLOATING IDLER PULLEY-Do not immerse the idler pulley in solvent. Use a rag containing solvent, clean the hole in the idler pulley and the shoulder bolt thoroughly. Useing a small amount of LAWN-BOY A GREASE or EQUIVALENT, relubricate the shoulder bolt and remount idler pulley assembly in the same order it was originally.

AS REQUIRED

1. CLUTCH LINKAGE-Apply several drops of light machine oil on clutch mechanism at all pivoting points.


PLASTIC BOLT-PULLEY-ARM-NUT The lower idler pulley on 8600 and 8601 models were plastic. It should not be lubricated after being removed and cleaned up. Never immerse plastic pulleys in solvent. Use a rag containing solvent to clean. If damaged and/or worn, replace with kit part no. 682564.

LOWER IDLER ASSEMBLY NEW STYLE

PART #682564 BOLT-PULLEY-ARM-NUT

LOWER IDLER PULLEY Permanently lubricated. No lubrication required.

10-41

UTILITY MODELS 4500,4501, 8600,8601 BLADE SERVICING

NOTE

BLADE ASSEMBLY

A totally new and different method of retaining the blade is used on the 20" utility model mowers.

The blade bolt, part no. 609960, is special with a SPECIFIC HARDNESS AND STRENGTH. The blade lockwasher, part no. 605339, is also special.

The lockwasher must be installed with TORQUE BLADE BOLT TO cupped surface and triangular points mounted 30-32 FT. LBS. toward the blade.

SAFETY WARNING

THE LOCKWASHER AND BLADE BOLT MUST BE REPLACED AFTER

STALLED FOUR (4) TIMES. THE LOCKING FEATURE OF THE LOCK- WASHER AND BLADE BOLT WILL HAVE DECREASED AND BLADE COULD LOOSEN IF REPLACEMENT IS NOT MADE.

BEING REMOVED AND REIN-


UTILITY MODELS 8602 AND LATER SELF-PROPELLED SERVICING On 4502,8602 and later models of Utility mowers, a blade nut has replaced the blade bolt previously used on earlier models.

SAFETY WARNING

THE BLADE NUT MUST BE RE- PLACED AFTER BEING REMOVED AND REINSTALLED FOUR (4) TIMES. THE LOCKING FEATURE OF THE BLADE NUT WILL HAVE DECREASED AND BLADE COULD LOOSEN IF REPLACEMENT IS NOT MADE.


models only)

A blade collar that was damaged and bent when being removed from crankshaft should always be replaced. If not replaced, a vibration in the mower and a rough, uneven or ragged cutting may result. KEEP BLADE SHARP AND BALANCED

Before assembling collar on crankshaft, check to be sure it did not get bent or distorted when being removed. If so, replace it. Do not use, because, it will cause vibration.

If the blade nut is to be re-used, clean the threads thoroughly. Also clean threads on crank shaft. Apply OMC Ultra-Lock Part No. 388517 on the threads.

NOTE

When installing blade after sharpening and balance, torque blade nut to 45-50 ft. lbs.

SAFETY WARNING

ALWAYS USE ORIGINAL EQUIP- MENT REPLACEMENT BLADE AND

SURE COMPLIANCE WITH SAFETY

STALLING BLADE, BE SURE PARTS ARE REPLACED IN THE SAME SE- QUENCE IN WHICH THEY WERE REMOVED. ALWAYS REPLACE BLADE WITH CURVED EDGE UP (TOWARD HOUSING).

ATTACHMENT HARDWARE TO IN-

SPECIFICATIONS. WHEN REIN-

10-43

SCAMP AND UTILITY MODELS

SERVICING 4502, 4503, 8602, 8603 WITH “F” SERIES ENGINES

SELF-PROPELLED BELT DRIVE

Adjustments and servicing of the Scamp and Utility self-propelled mowers are very different from all previous models of self-propelled mowers.

SAFETY WARNING

BEFORE ANY ADJUSTMENTS OR REPAIRS ARE ATTEMPTED, DIS- CONNECT AND REMOVE SPARK PLUG TO PREVENT STARTING.



2. Align hole in clip with hole in arm and assemble lower end of the control rod in hole.


SAFETY WARNING

THE LOWER SELF PROPEL CON- TROL ROD MUST BE ASSEMBLED TO CLUTCH ARM AS SHOWN. I F NOT THE SELF PROPEL MECH- ANISM WILL NOT RETURN TO NEUTRAL WHEN THE CONTROL LEVER IS RELEASED FROM THE ENGAGED POSITION.

10-44 REVISED 1983


4. With the control handle in "neutral" (free) position a s shown.


SERVICING 6. Secure upper and lower control rods together with the clamp screw as shown. This screw should be tightened securely

SELF=PROPELLED BELT DRIVE

by hand.


SAFETY WARNING

IMPROPER TIGHT.ENING OF CLAMP SCREW ON CONTROL ROD MAY RESULT IN OPERATOR LOSS OF DRIVE CONTROL MECHANISM.

NOTE

To put mower in motion, pull upward on control handle and hold in drive position. To stop forward motion of mower, release control handle. Mower drive mechanism functions only when the control handle is held in "DRIVE" position.

!




1. With the control handle in "Neutral", place both rear wheel height adjusters in #1 (lowest) cutting position as shown. A gap of 3/16" should appear between the drive rollers and t ires.

2. Loosen bolt and nut located in drive roller gap adjusting slot on each side of drive roller bracket.

3. Move the drive roller bracket up o r down to obtain the necessary 3/16'' drive roller gap. Hold bracket in position and tighten both bolts and nuts securely.

ENGINE REMOVAL OR REPLACEMENT

SAFETY WARNING

TO PREVENT STARTING OF EN- GINE, DISCONNECT AND REMOVE SPARK PLUG PRIOR TO REMOVING THE ENGINE.

1. Remove blade bolt, washer, blade stiffener, collar and three bolts securing muffler and remove muffler.

n


Do not remove muffler plate from housing when removing engine.





SAFETY WARNING

TO PREVENT STARTING ENGINE, DISCONNECT SPARK PLUG LEAD AND REMOVE SPARK PLUG.

The "V" belt used on the utility self- propelled model mowers is a SPECIAL BELT. DO NOT USE A SUBSTITUTE. It won't work as WELL o r a s LONG.

To remove the belt:



SAFETY WARNING

DO NOT OPERATE MOWER WITH BELT GUARD REMOVED.


4. Remove belt from driven pulley and slide shaft assembly to the right. Remove belt from mower a s shown.


REVISED 1983



NOTE

After the belt has been removed, examine for broken, cracked or misaligned pulleys. The condition and the wear pattern of the belt will provide clues for the above possibilities. Replace damaged o r worn pulleys.

5. The crankshaft pulley (drive pulley) is secured to the crankshaft with a SPECIAL slotted set screw. The end of this screw locates in a hole in the crankshaft. The correct position and tightness is very IMPORTANT. If not tightened securely, damage to the pulley, crankshaft and premature wear of the drive belt will result.

NOTE

Apply OMC Ultra-Lock (part no. 388517) to threads of set screw prior to installation.

6. When reinstalling pulley to crankshaft, the side of the pulley with set screw is the lower side. If assembled upside down (set screw on top) misalignment and interference of pulley operation will result. Always check pulley for damage. Replace if necessary.

10.48 REVISED 1983


IDLER PULLEYS TOP STRAND



SAFETY WARNING

INCORRECT DRIVE BELT INSTAL- LATION MAY ALLOW MOWER TO OPERATE IN REVERSE DIRECTION

TOR OR BYSTANDERS. ASSEMBLE DRIVE BELT AS SHOWN.

CAUSING INJURY TO THE OPERA-

DRIVE- BOTTOM STRAND ENGINE SHAFT DRIVE PULLEY PULLEY


8. Check the condition of the driveshaft, bronze bearings, and sleeve. If signs of damage or wear appear, replace them.

7. Place belt over left end of drive shaft as shown. Do not assemble on driveshaft pulley.

9. BUSHING AND BEARING INSTALLA- TIONS.

NOTE

The sleeve has a flat surface that matches the flat surface of the bracket. When reassembling, the flat surfaces must match.


SERVICING SELF=PROPELLED BELT DRIVE



12. Using a new roll pin, assemble the drive roller to the drive shaft. Use a 5/32” or larger drift punch, drive the roll pin into place, flush with the outer surface. Neither end should protrude beyond the roller surface.


13. As you face the front of the mower, twist the forward end of the belt 1/4 turn counter clockwise and assemble on the engine drive pulley. Assemble engine on muffler plate and secure with three bolts.

14. Release spring tension on idler pulleys and assemble belt on drive shaft pulley. Reassemble idler pulley spring and rotate the belt several revolutions. Check to make sure the belt is centered on the pulleys and TURNING IN RIGHT DIREC- TION. Note direction of arrow on large pulley in illustration above. Check and adjust belt tension if necessary. Refer to BELT TENSION ADJUSTMENT.

When replacing either of the belt idler assemblies, use idler kit part no. 682374 for the top and kit part no. 682564 on the bottom.

10.50 SERVICE BULLETIN REFERENCES REVISED 1983

BELT TENSION ADJUSTMENT

1. Check drive belt installation. Drive belt must be installed between idler pulleys as shown.

2. Drive belt should be checked to insure that proper tension exists in order to prevent premature belt failure. Lift floating idler from the upper strand of "V" belt. Belt will then become loose. Set floating idler onto "V" belt and check clearance between the two strands of the "V" belt. The distance between the two strands should not be less than 1/2" as shown.



3 . To adjust belt tension; loosen four handle bracket mounting screws (two on each bracket) and two screws (one on each side) located on the sides of rear height adjuster bracket as shown. Slide entire self-propelling mechanism in direction necessary to obtain the proper "V" belt tension.

4. Care should be taken to insure that both sides of the self-propelling mechanism a r e positioned equally on the mower housing. This can be accomplished by measuring the distance from the front edge on the height adjuster brackets to the' 1/4" diameter gage holes located directly in front of these brackets as shown. This distance must be the same for both sides. Before tightening screws make sure the distance between the strands of the "V" belt is not less than 1/2". Tighten the four handle bracket screws and the two side screws securely. Reassemble belt guard to self-propel mechanism using screws previously removed.

SAFETY WARNING DO NOT OPERATE MOWER WITH BELT GUARD REMOVED.

SERVICE BULLETIN REFERENCES 10.51 REVISED 1983



LUBRICATION

10 HOURS

1. DRIVE ROLLER BEARINGS-Disassemble rotating shaft cover from self-propel mechanism by removing four screws. Unscrew plug from end of each drive roller (Point “A”). Fill exposed cavity

610721 OR EQUIVALENT. Replace plug and tighten until snug. Repeat procedure until lubricant appears on cross-shaft at Point “B”. Reas- semble rotating shaft cover to self-propel assembly.

with LAWN-BOY “A” GREASE, PART NO.

FLOATING IDLER PULLEY-Do not immerse the idler pulley in solvent. Use a rag containing solvent, clean the hole in the idler pulley and the shoulder bolt thoroughly. Useing a small amount of LAWN-BOY A GREASE or EQUIVALENT, relubricate the shoulder bolt and remount idler pulley assembly in the same order it was originally.

AS REQUIRED

1. CLUTCH LINKAGE-Apply several drops of light machine oil on clutch mechanism a t all pivoting points.

10-52

NEW STYLE LOWER IDLER ASSEMBLY

PART #682564 BOLT-PULLEY-ARM-NUT

LOWER IDLER PULLEY Permanently lubricated. No lubrication required.


UTILITY MODELS 4502 AND 8602 SCAMP MODELS 4503 AND 8603

SELF-PROPELLED SERVICING On 4502,4503,8602,8603 models of Utility and Scamp mowers, a blade nut has replaced the blade bolt previously used on earlier models.

SAFETY WARNING

THE BLADE NUT MUST BE RE- PLACED AFTER BEING REMOVED AND REINSTALLED FOUR (4) TIMES. THE LOCKING FEATURE OF THE BLADE NUT WILL HAVE DECREASED AND BLADE COULD LOOSEN IF REPLACEMENT IS NOT MADE.


models only)

Before assembling collar on crankshaft, check to be sure it did not get bent or distorted when b e ing removed. If so, replace it. Do not use, because, it will cause vibration.

If the blade nut is to be reused, clean the threads thoroughly. Also clean threads on crank shaft. Apply OMC Ultra-Lock Part No. 388517 on the threads.

NOTE

When installing blade after sharpening and balance, torque blade nut to 45-50 ft. 1bS.

SAFETY WARNING

ALWAYS USE ORIGINAL EQUIP- MENT REPLACEMENT BLADE AND ATTACHMENT HARDWARE TO IN- SURE COMPLIANCE WITH SAFETY

STALLING BLADE, BE SURE PARTS

QUENCE IN WHICH THEY WERE REMOVED. ALWAYS REPLACE BLADE WITH CURVED EDGE UP (TOWARD HOUSING).

SPECIFICATIONS. WHEN REIN-

ARE REPLACED IN THE SAME SE-

A blade collar that was damaged and bent when being removed from crankshaft should always be replaced. If not replaced, a vibration in the mower and a rough, uneven or ragged cutting may result.

KEEP BLADE SHARP A N D BALANCED REVISED 1983 10-53

CONTENTS OF RIDING MOWER SECTION

MODELS 9300, 9301

Models 9300 and 9301 are powered by a 4 cycle 6 H P gasoline engine. For engine servicing o r repair, contact your local Briggs and Stratton dealer or the Briggs and Stratton Corporation, Milwaukee, Wisconsin.

MODEL 9301 ILLUSTRATED

MODEL 9302 Model 9302 is powered by a 4 cycle 7 H P gasoline engine. For engine servicing or repair, contact your local Briggs and Stratton dealer or the Briggs and Stratton Corporation, Mil- waukee, Wisconsin.

MODEL 9302E Model 93023 is powered by a 4 cycle 7 HP gasoline engine. For engine servicing or repair, contact your local Tecumseh dealer or the Lauson-Power Products Division, Grafton, Wisconsin.

MODEL 9303E

MODEL 9600

MODEL 9601 Model 9601 is powered by a 4 cycle 5 HP gasoline engine. For engine servicing or repair, contact your local Briggs and Stratton dealer o r the Briggs and Stratton Corporation, Mil- waukee, Wisconsin.

11-ii SERVICE BULLETIN REFERENCES REVISED 1977

CONTENTS OF RIDING MOWER SECTION

MODELS

Models 9328, 93283, 9328ES, 9368, 9368E and 9368ES compact riders are propelled by a geared transmission with three forward speeds and reverse. Maximum speed in first gear is: 2.6 MPH, second gear 4.0 MPH, third gear 5.9 MPH and reverse gear 2.6 MPH.

The 32 o r 36 inch floating pan may be adjusted to 5 different cutting positions between 1-3/8 inches and 2-7/8 inches. The front wheels a re semi-pneumatic while the rear tires are fully pneumatic and maintain 16-18 pounds air pressure.

11-iii

TABLE OF

CHAPTER I MODEL 9300 ONLY

THEORY OF OPERATION ADJUSTMENTS

P a n Tilt Blade Brake Adjustment Speed Selector Lever Brake Adjustment Steering Wheel Alignment

TIRES AND WHEELS TO REMOVE OR CHANGE

B E L T STEERING PROBLEMS

Steer ing Gear Disassembly Reassembly

MOWER PAN REMOVAL DRIVE CHAINS DRIVE BRACKET DRIVE ROLLER

REPLACEMENT INTERMEDIATE DRIVE SHAFT

REPLACEMENT DIFFERENTIAL BLADE ENGINE

CHAPTER II MODELS 9301. 9302. 9302E. 9303E. 9600. 9601 ONLY

SECTION 1

TROUBLESHOOTING STEERING MOWERPANANDBLADE DRIVE PROBLEMS FUEL PROBLEMS IGNITION PROBLEMS LUBRICATION

SPECIFICATIONS BOLT AND NUT TORQUES ENGINE

SPECIFICATIONS TIRE SPECIFICATIONS BATTERY SPECIFICATIONS

SECTION 2

HOW TO REPAIR AND R E P L A C E . .

STEERING STEERING DISASSEMBLY SPINDLE AND/OR KING PIN

REMOVAL

11-1 11-2 11-2 11-3 11-3 11-4 11-4 11-5

11-6 11-8 11-9 11-10 11-11 11-11 11-12

11-12

11-14 11-15 11-16 11-16

11-17 11-17 11-17 11-18 11-19 11-20

11-21 11-21

11-21 11-22 11-22

11-23 11-23 11-25

11-25

CONTENTS

FRONT AXLE REMOVAL STEERING CASTING

REMOVAL STEERING CASTING

DISASSEMBLY STEERING WHEEL

ALIGNMENT

SECTION 3

ADJUSTMENTS POWER FOR DRIVING THE

MOWER BLADE MOWER PAN DISASSEMBLY FRONT BELT REMOVAL REAR BELT REMOVAL IDLER ARM REMOVAL PAN REMOVAL FRONT BELT REMOVAL BLADE BRAKE ADJUSTMENT PAN TILT ADJUSTMENT

26" AND 30" MODELS

SECTION 4

THEORY OF OPERATION INTRODUCTION POWER FOR DRIVING THE

WHEELS PRIMARY DRIVE SERVICING DISC COMPRESSION SPRING

REMOVAL RUBBER DRIVE ROLLER

SERVICE

MENTS DRIVE ASSEMBLY ADJUST-

DRIVE ROLLER TRAVEL HORIZONTAL

VERTICAL

SPRING TENSIONS SECONDARY DRIVE

SERVICING INTERMEDIATE DRIVESHAFT

REPLACEMENT CHAIN ADJUSTMENT ON

PRIMARY AND FINAL DRIVE ONLY



WHEEL 'BRAKE

FINAL DRIVE DISASSEMBLY DIFFERENTIAL REMOVAL

ADJUSTMENT

11-25

11-25

11-25

11-26

11-27

11-27 11-29 11-29 11-29 11-29 11-29 11-29 11-30

11-31

11-32 11-32

11-32 11-38

10-38

11-38

11-39

11-39

11-40

11-43

11-46

11-46

11-46

11-46 11-48 11-48

11-iv SERVICE BULLETIN REFERENCES REVISED 1977

TABLE OF CONTENTS cont

DIFFERENTIAL DISASSEMBLY 11-48

ENGINE REMOVAL 11-49 DRIVE DISC REMOVAL 11-49 DRIVE PULLEY REMOVAL 11-49

SECTION 5

ELECTRICAL SERVICING 11-50 INSTALLING NEW DIODES 11-51 INSTALLING REPLACEMENT

FUSE 11-51

SECT ION 6

PREVENTIVE MAINTE- NANCE

CRANKCASE OIL BLADECARE LUBRICATION TIRES BATTERY DIFFERENTIAL FRICTION DRIVE BLADE BLADE REMOVAL BENTBLADE

11-52 11-52 11-52 11-52 11-52 11-52 11-52 11-53 11-53 11-53 11-54

CHAPTER 111 MODELS 9500. 9501 ONLY

BLADE HOUSING AND BLADE DRIVE PROBLEMS FUELTROUBLE SPARK PLUG TROUBLE

SECTION 6

FRONT END STEERING SPINDLE & STEERING ARM

REMOVAL FRONTAXLE REMOVAL STEERING CASTING &

STEERING SHAFT REMOVAL STEERING WHEEL

ALIGNMENT

SECTION 7

BLADE DRIVE AND BLADE HOUSING ASSEMBLY

BELT REPLACEMENT F R O N T B E L T R E A R B E L T BLADE HOUSING REMOVAL BLADE PULLEY SPINDLE TO

BEARING REMOVAL BLADE HOUSING

HEIGHT (CUTTING) ADJUSTMENT

SECTION 1 SECT ION 8

INTRODUCTION 11-55

SECTION 2

SPECIFICATIONS 11-56 ENGINE 11-56 TIRE 11-56

SECTION 3

LUBRICATION 11-56 SPECIFICATIONS 11-56

SECTION 4

HARDWARE TORQUES 11-57

SECTION 5

TROUBLESHOOTING 11-58 STEERING 11-58

TRANSMISSION TRANSMISSION DRIVE B E L T TRANSMISSION B E L T

IDLER ADJUSTMENT TRANSMISSION PULLEY

REPAIR OR REPLACEMENT INTERMEDIATE SPINDLE &

PULLEY ASSEMBLY REAR BLADE DRIVE

BELT PULLEY IDLER & BRAKE ASSEMBLY

BLADE BRAKE ADJUSTMENT BLADE CLUTCH

IDLER ADJUSTMENT THROTTLE CONTROL

ADJUSTMENT ENGINE REMOVAL TRANSMISSION DISASSEMBLY SHIFT HANDLE REMOVAL TRANSMISSION GEARBOX


11-58 11-59 11-60 11-60

11-62 11-62

11-62 11-62

11-62

11-64

11-66 11-67 11-67 11-67 11-67

11-67

11-67

11-70 11-70

11-70

11-70

11-70

11-71 11-71

11-71

11-71 11-71 11-74 11-74 11-74

. 11-v

TABLE OF CONTENTS cont.

SECTION 9 SECT ION 6

WHEEL BRAKE 11-75 BRAKE ADJUSTMENT. 11-75

STEERING. STEERING DISASSEMBLY

SECTION 7 SECTION 10

DIFFERENTIAL. 11-76 REMOVING DIFFERENTIAL

DRIVE SPROCKET 11-76 DIFFERENTIAL REPAIR. 11-76 LUBRICATING DIFFERENTIAL 11-76 DRIVE CHAIN TENSION 11-79 REAR WHEEL BEARING &

AXLE LUBRICATION 11-79

CHAPTER IV MODELS 9328, 9328E, 9328ES, 9368, 9368E, 9368ES ONLY

BLADE DRIVE & BLADE HOUSING ASSY.

BELT REPLACEMENT Pr imary Blade Dr ive Belt Final Blade Drive Belt

Replacement Transmission Drive Belt

Replacement CUTTING HEIGHT ADJUSTMENT LUBRICATION O F BLADE

SHAFT' HOUSING ASSY. BLADE SERVICING

SECTION 8 SECTION 1

INTRODUCTION.. 11-80

SECTION 2

SPECIFICATIONS, 11-81

SECTION 3

LUBRICATION

SECT ION 4

HARDWARE TORQUES

SECTION 5

TROUBLESHOOTING.

BLADE HOUSING AND BLADE DRIVE PROBLEMS. FUEL TROUBLE SPARK PLUG TROUBLE

STEERING.

11-81

11-82

11-83 11-83 11-83 11-84 11-85 11-85

TRANSMISSION TRANSMISSION REPAIR OR

REPLACEMENT TRANSMISSION LUBRICATION MOWER ,BRAKE PARKING BRAKE CLUTCH,.

SECTION 9

DIFFERENTIAL. . DIFFERENTIAL REPAIR OR

REPLACEMENT.. DIFFERENTIAL LUBRICATION DRIVE CHAIN ADJUSTMENT DRIVE CHAIN REPLACEMENT. THROTTLE CONTROL

ADJUSTMENT

SECTION 10 WIRING DIAGRAMS.

CHAPTER V

STORAGE PROCEDURE.

11-87 11-87

11-89 11-89 11-89

11-90

11-90 11-90

11-91 11-91

11-93

11-93 11-93 11-93 11-93 11-93

11-95

11-95 11-95 11-95 11-95

11-95

11-96

11-98

l l -v i SERVICE BULLETIN REFERENCES REVISED 1977

CHAPTER I MODEL 9300 ONLY

The Riding Mower is powered by a 4 cycle gasoline engine, Power to drive the rear wheels is derived from a rubber tired roller driven by a disc attached to the engine crankshaft, and transmitted by chain to the rear wheels. Mower travel speed is controlled by the speed selector which is linked to the drive roller. As the speed selector. is shifted, the drive roller is moved across the face of the drive disc, thus varying the drive roller RPM.

The blade is belt driven from a pulley on the crankshaft. Blade speed is controlled by engine RPM, NOT MOWER TRAVEL SPEED, The blade control lever is a posi-

tive engagement over-center type of control. An idler pulley linked to this control applies tension to the belt when the. lever is in the "down" position and removes tension when the lever is moved to the “UP” position. The blade brake is applied when the blade control lever is in the "up" position.

Brake and clutch foot pedals used for emer- gency stopping and uphill starts are located adjacent to the steering column, The throttle is located on the main frame midway between the steering column and operator's seat, The height adjusting lever on the pan provides five different cutting heights from 1-1/2 inches to 3-1/2 inches. The mower pan is free floating which prevents scalping.


11-1

MODEL 9300 ONLY The riding mower has a unique feature which greatly simplifies service and repair. The exclusive knurfing bar, Figure 1-1 and curved contour combined with weight con- centration at the rear of the mower, makes it possible to tip the mower on end. Virtually all maintenance can be performed while mower is standing on end, from blade removal to complete overhaul. See Figure 1-2.

NOTE

Do not tip mower on either side. Engine oil will run into the cylinder and carburetor.

ADJU PAN TILT

FIGURE 1-1

STM

Correct pan tilt: Measure the distance from the ground to the top of the cutout at the front of the pan, and from the ground to the bottom edge at the rear of the pan. The measurement at the rear of the pan must be 1/8 inch less than the front measurement. This will provide a 1/4 inch tilt to the pan and prevent double cutting. See Figure 1-3.

NOTE

Always adjust pan tilt on a flat level surface,

FIGURE 1-2

ENTS

To adjust tilt:

1. Remove cotter pin and washer from one end of adjusting rod.

2. Loosen locknut and turn rod in or out of the turnbuckle as required to obtain the proper pan tilt. See Figure 1-4.

3. Install the rod in the bracket and secure with cotter pin and washer.

Pan tilt adjustment can be made with height adjusting lever in any of the five positions.


MODEL 9300 ONLY BLADE BRAKE ADJUSTMENT

1. Shut off engine by placing throttle control lever in STOP position.

2. Place blade control lever in OFF position.

3. Place speed selector in NEUTRAL.

4. Be certain blade attaching nut is secure.

5. Loosen both front and rear locknuts.

6. Restart engine. Set throttle control "FAST" position.

7. The front adjustment nut should be just snug against the stop, loosen o r tighten as required to obtain blade stoppage in not less than 6 or more than 10 seconds with engine operating at 3600 RPM. See Figure 1-5.

SAFETY WARNING BLADE STOPPAGE CHECK SHOULD BE MADE VISUALLY BY OBSERV- ING DRIVE PULLEY. DO NOT PLACE HANDS UNDER HOUSING.

c. Turn the ball joint onto the rod to lengthen travel off the rod to shorten travel, Proper adjustment should place the drive disc exactly over the center of the drive plate ± 1/16" when speed selector lever is in the "neutral" position.

8. When proper adjustment is obtained se- d. When proper adjustment is reached, attach ball joint to the bell arm as-

9. Place blade control lever in RUN posi- sembly and tighten nut securely. Tighten jam nut against the ball

curely tighten front locknut.

tion. socket.

10. Loosen rear adjustment nut on blade control rod and then tighten it until it just makes contact with the stop, then tighten one turn more. Securely tighten rear locknut. See Figure 1-5.

SPEED SELECTOR LEVER

1. Drive Roller Travel. a. Place the speed selector lever in

“neutral” and loosen the jam nut on the speed control rod.

b. Remove the nut securing ball stud to the bell arm assembly. See Figure 1-6.

MODEL 9300 ONLY 2. Drive Bracket Travel.

a. Place the speed selector lever in neutral position.

b. Loosen the upper and lower nuts on the reverse booster spring and on the speed clutch control rod. See Figure

c. Insert a 3/32 inch spacer between the drive disc and drive roller. Tighten the upper nut on the reverse booster spring until the spacer is held between the disc and roller.

d. Tighten the upper nut on the speed clutch control rod until the 3/32 inch spacer falls from between the drive disc and drive roller,

e. Tighten the lower nuts on the reverse booster spring and the speed clutch control rod.

1-7.

BRAKE ADJUSTMENT

1. Remove the cotter pin and washer from the brake rod at the foot pedal. See Figure 1-8.

2. Loosen the jam nuts at the turnbuckle, and turn the front brake rod into or out of the turnbuckle. See Figure 1-9. Proper adjustment is obtained when slight pressure on the pedal encounters resistance after 1/2 inch pedal travel.

3. Tighten the jam nuts at the turnbuckle and reassemble the brake rod to the foot pedal,

STEERING WHEEL ALIGNMENT

If the steering wheel does not line up properly with the front wheels, it can be aligned as follows:

1. Remove the nut securing ball joint to king pin arm. See Figure 1-10.

2. Loosen the jam nut at the ball joint socket and turn the ball joint onto o r off the rod until the steering wheel is aligned with the front wheels.

3. Assemble the ball joint to the king pin arm and tighten the j a m nut.

BRAKE PEDAL

FIGURE 1-8

TURNBUCKLE

JAM NUT-


MODEL 9300 ONLY TIRES AND WHEELS TIRES

The tires should be inspected for cuts, abrasions and other damage whenever mower is serviced. Make sure the t ires are inflated to the recommended pressure. Front tire pressure is 15-17 lbs. Rear tire pressure is 22-25 lbs. Check t ires with a tire pressure gauge. DO NOT over- inflate tires. Unless you are properly equipped to repair the tires, it is recommended that repair be accomplished by a service station or tire shop equipped to handle t ires of this size.

FRONT WHEEL REMOVAL

To remove front wheels, insert a screwdriver in the “E” shaped retaining ring and pry the ring off the spindle.

SAFETY WARNING CUP YOUR HAND AROUND THE RING TO PREVENT LOSS OF IT OR POSSIBLY INJURING YOU OR A BYSTANDER.

See Figure 1-11. Slide the wheel off the spindle.

Inspect the spindle and wheel bushing for signs of wear. Replace bushings if they are badly worn. See LUBRICATION SPECIFI- CATIONS on Page 11-21.

94230

REAR WHEEL REMOVAL To remove the rear wheels, tip the mower up on end. Remove the nuts and washers holding the wheels on the axles. See Figure 1-12. Use a hard rubber or rawhide mallet and drive the wheel off the axle. Turn the wheel while striking it so it is driven off evenly. The rear wheels are keyed to the axles and require considerable force to drive them off the axle.

SAFETY WARNING WHEN STANDING MOWER ON END, ALWAYS ANCHOR IT TO PREVENT FROM TIPPING OR FALLING. ALSO

TION AND DISCONNECT SPARK PLUG LEAD.

PLACE THROTTLE IN “STOP” POSI-

NOTE Axles may be equipped with-Wood- ruff Keys (HALF MOON) o r Straight Keys. See Figures 1-13 and 1-14.

Whenever the rear wheels are removed, examine the keys and the keyslots in the axle and wheel. If key is worn, it should be replaced. If the keyslot in the axle o r wheel becomes damaged o r excessively worn the worn part must be replaced. Prior to replacing rear wheels apply a thin coat of Lawn-Boy “A” grease for easy removal at a later time.

MODEL 9300 ONLY RIDING MOWER V-BELT The riding mower V-belt is a special belt selected for strength and durability. Don't use a substitute it will not last as long nor work as well. Frayed or worn belts should always be replaced.

SAFETY WARNING ALWAYS PLACE THROTTLE CON-

,/ TROL IN "STOP" POSITION AND DISCONNECT SPARK PLUG LEAD BEFORE INSPECTING OR REPAIR- ING THE MOWER.

TO REMOVE OR CHANGE BELT

2. Insert a screwdriver or wrench under the belt retaining rod, and apply pressure until rod slips out of notch in the belt cover. Remove the rod from the housing. See Figure 1-16.

5. Loosen (DO NOT REMOVE) the bolts securing the knurfing bar and rear cover to the rear housing.

1. Place blade control lever in "off" position, anti remove the two front nuts from

6. Swing the rear cover down and remove it. Retighten the knurfing bar bolts. See Figure 1-18.

11-6 REVISED 1977

3. Remove the bolts securing the belt cover to the pan. Lower the pan by moving the height adjusting lever forward to the lowest setting, and remove the belt cover.

4. Slip the belt off the front pulley. See Figure 1-17.

KNURFING BAR BOLTS

FIGURE 1-18


MODEL 9300 ONLY

8. Remove the bolts securing the belt keeper housing and slide the belt keeper out of the rear. See Figure 1-20.

11. Move the speed selector lever to the 3rd speed position. This will move the drive roller toward the outside of the drive disc. Slide belt between the drive disc and drive roller.

12. If belt will not pass between the disc and roller, pull outward on the drive bracket a s shown in Figure 1-22.

Reverse the procedure to install new belt and adjust blade brake,

9.

7. Slip a length of rope through the eye of the disc compression spring and free the spring a s shown in Figure 1-19.

10.

Stand the mower up on end.

SAFETY WARNING

WHEN STANDING MOWER ON END, ALWAYS ANCHOR IT TO PREVENT FROM TIPPING OR FALLING. ALSO



Twist the belt so the flat sides can pass tween the idler pulley and the drive disc. Figure 1-21.

be- See

SERVlCE BULLETlN REFERENCES 11-7 REVISED 1977

MODEL 9300 ONLY

STEERING PROBLEMS

The steering system on the riding mower is axis.' If there is no movement, bush- a geared system. A pinion on the steering ings :are satisfactory. If there is ex- ? shaft meshes with a rack on the pitman arm, cessive movement, the bushings must The pitman arm in turn is linked to the left be replaced. Refer to topic Steering side spindle, and a tie rod connects the Gear Disassembly. wheels.

Most steering problems can be traced to one of the following conditions. b. Worn Wheel Bushings in Wheels. This

condition will result in individual 1. Dirt Build-up in Steering Gear. This

condition occurs because the frame castings are not sealed. Over a period of time, dust, dirt, grass clippings and other debris can accumulate in the steering gear. The only corrective action for

wheel wobble when the mower is in motion. To check, stand the mower on end, grasp the front wheel, and attempt to tilt it back and forth on the axle. If the wheel bushing is worn, it must be replaced.

this condition is complete disassembly and cleaning of the steering gear. Refer to topic Steering Gear Disassembly. c. Bent Tie Rod. A bent tie rod will cause toe-out

of the wheels. Check the tie rod for straight- Damaged Steering Gear Components. ness. If bent, remove it and straighten in a vise Worn or broken steering components can or replace it. cause hard or erratic steering. Look for: a. Worn spindle bushings in axle. These d. Worn o r Broken Teeth on Steering

can easily be recognized by standing Gear or Pitman Arm Rack. Gear wear the mower on end, grasping the front or damage can only be checked by wheel, and attempting to move the disassembling the steering gear and wheel in a direction parallel to its visually inspecting the gears.


MODEL 9300 ONLY STEERING GEAR DISASSEMBLY

SAFETY WARNING



PLACE THROTTLE IN “STOP’ POSI-

1. Stand the mower on end, Figure 1-23, and remove the front wheels by prying out the E rings and sliding the wheels off the spindles.

2. Disconnect the clutch and brake rods at the foot pedals.

3. Remove the steering wheel by removing the two nuts and bolts securing it to the lower shaft.

4. Remove the “U” bolt holding the foot res t to the frame. 9422 FIGURE 1-23

5. Remove the E shaped retaining ring from one end of the pedal and foot rest support and carefully drive the support out of the foot rest pedal, and frame casting.

6. Disconnect the tie bar and tie rod at each king pin arm.

7. Drive out roll pin from one king pin arm and spindle, as shown in Figure 1-24 and remove the king pin arm and spindle.

8. Pry out the E shaped ring from one end of the pin securing the axle to the main frame castings, Figure 1-25, loosennuts on bolts holding castings together, slip pin out, Figure 1-26, and slide the axle out of the frame castings.

MO 9.

10.

11.

12.

DEL 9300 ONLY Remove the two rear bolts through the frame casting, and slide the frame casting from the frame.

Remove the nuts, from the bolts remaining in the frame casting leaving the bolts in place. Place the frame casting on the floor o r on a workbench with the bolt heads down, and separate the halves of the casting to expose the steering gear. See Figure 1-27.

Remove the lower shaft with bushing on the shaft, and lift the pitman arm, shaft and washer from the frame casting.

Thoroughly clean the inside of the casting halves, and wash the steering components with a-suitable solvent.

NOTE

DO NOT WASH OR WIPE BUSHINGS WITH SOLVENT. THEY ARE OIL IMPREGNATED AND WILL LOSE LUBRICANT.

13. Examine the steering gear and pitman arm for chipped, cracked, or excessively worn teeth, and replace parts if necessary. Inspect all steering system bushings, pins, etc. for signs of wear. FIGURE 1-27

REASSEMBLY 1. Install the steering lower shaft and pitman arm est to the head of the screw must be inside the

in the bottom casting half. MAKE SURE THE first tooth of the pitman arm. See Figures 1-28, STEERING GEAR AND PITMAN ARM 1-29 and 1-30. Otherwise the mower will not ARE IN PROPER MESH. There is only one turn equal distance in both directions. correct method of installation. The tooth clos-

MODEL 9300 ONLY

2.

3.

4.

Once the steering gear and pitman arm ARE properly meshed, apply a liberal coating of Lawn-Boy “A” grease to them.

Reassemble the rest of the steering components in the reverse order of disassembly. Test it by turning the wheel to make sure it is operating properly.

Grease the front wheel spindles when mower is completely assembled, using a grease gun. See Figure 1-31.

MOWER PAN REMOVAL

1. Remove belt as described under Riding Mower V-Belt section. To remove mower pan, pry E ring out of the support rod and slide rod out of pan suspension bar a s shown in Figure 1-32.

2. Remove the two pivot bolts securing pan to the rear housing a s SHOWN in Figure 1-33 and allow the pan to drop to the floor.

3. To replace spindle, remove blade and three bolts securing spindle housing to pan. Remove two bolts attaching support bars to spindle and lift spindle from pan.

DRIVE CHAINS

Two drive chains transmit power from the drive roller wheel to the rear wheels. An occasional light coating of oil on the chains will keep them in operating condition for years.

If it becomes necessary to remove a chain, locate the master link, Figure 1-34, pry the retaining spring out of the chain link grooves, and remove the master link.

m e n installing a master link, make sure the split end of the retaining spring is facing away from the direction of travel of the chain.


MODEL 9300 ONLY

94224 FIGURE 1-35

DRIVE BRACKET

The drive bracket contains 'the drive roller, hex shaft, and intermediate drive shaft. These components transmit power from the engine to the rear wheels. See Figure 1-35.

It is not necessary to remove the drive bracket from the mower to service the drive roller. However, the drive bracket must be removed for intermediate shaft service.

Drive Roller Service. Periodic inspection of the rubber roller and regularly scheduled lubrication of the felt oiler pad on the drive roller are the only regular maintenance operations on the drive roller.

MODEL 9300 ONLY

4. Disconnect the speed selector, reverse booster and clutch rods from the drive bracket. See Figures 1-37, 1-38 and 1-39.

DRIVE ROLLER

5. Remove the intermediate drive chain.

6. Swing the drive bracket down away from the housing as shown in Figure 1-40.

7. Remove the bolts securing the speed selector linkage to the drive roller bearing block. See Figure 1-40 and 1-41.

8. Remove the bolts mounting the bearing retainer at the sprocket end of the hexagonal shaft. Refer to Figure 1-36.

9. Pull the hexagonal shaft out of the drive bracket. Catch the drive roller as it slides off the shaft.

10. Remove the screws holding the drive roller to the bearing block and separate the drive roller, felt oiler pad and pad retainer.

11. Wash felt retainer pad in solvent and allow to dry. Rub a small amount of petroleum jelly into pad. See Figure 1-41.

12. Assemble new roller, the felt oiler pad and pad retainer to the bearing block.

13. Install parts in reverse order of removal, and adjust clutch and speed selector.


MODEL 9300 ONLY INTERMEDIATE DRIVE SHAFT REPLACEMENT

If it becomes necessary to replace the intermediate drive shaft, the following procedure should be used.

1. Perform steps 1 through 5 under drive roller replacement.

2. Remove final drive chain.

3. Remove bolts mounting the brake shoe to the housing and swing' brake shoe out of the way. See Figure 1-42.

4. Remove bearing retainer from sprocket end of intermediate shaft.

5. Pull on' intermediate shaft and drive bracket 'until bearing is free of housing, and remove the bearing. See Figure 1-43. Remove the shaft and bracketfrom the housing.

I

6. Drive out the roll pin securing the brake drum to the shaft. Remove the drum and bellville washers. See Figure 1-44. Pull the intermediate shaft out of the drive bracket.

7. Replace any defective parts and reinstall in reverse order of removal. Make sure the concave surfaces of the bellville washers are facing each other when installing brake drum. Adjust the clutch, speed selector, and brake, if necessary.

94201

11-14. SERVICE BULLETIN REFERENCES REVISED 1977

DIFFERENTIAL To remove the differential: 1. With mower in horizontal position,

loosen but do not remove, the knurfing bar mounting bolts, and remove the back cover.

2. Remove the bolts securing the belt keeper to the rear housing, and remove the belt keeper. Retighten knurfing bar bolts.

3. Thread a length of rope through the eye of the disc compression spring and release the spring from the housing.

4. Stand the mower up on end and perform steps 4 through 6 under the topic DRIVE ROLLER REPLACEMENT.

5. Remove the screw securing the drive disc to the engine crankshaft, and pull the disc off the crankshaft. DO NOT LOSE THE KEY. Pull the belt forward after disc is free of the crankshaft.

6. Remove the bolts securing the center bearing bracket to the housing. See Figure 1-45.

7. Remove the final drive chain. 8. Remove the rear wheels as described in

the topic TIRES AND WHEELS. 9. Move the differential end of the drive

shaft away from the housing. This will free the bearing at the opposite end of the shaft, Continue moving the shaft until the differential end of the shaft clears the housing. As the shaft is moved, slide the center bearing bracket toward the differential. If interference with the blade control lever spring is encountered, move the lever until the spring can be cleared. See Figure 1-46.

10. Free the opposite end of the drive shaft from the housing. Slide center bearing bracket off the shaft.

11. Remove the four bolts securing the differential to the sprocket. Slide the sprocket off the shaft to expose the internal differential parts. See Figure 1-47. The parts may be washed in a mild solvent, dry thoroughly and apply a minimum of three ounces of Lawn-Boy “A” grease when reassembling.

FIGURE 1-47

12. Install the differential in reverse order of removal. When installing drive disc make sure belt is seated on the pulley before tightening down disc.


MODEL 9300 ONLY BLADE

Always keep blade sharp and balanced. A bent blade will cause vibration and loss of power. Check balance and grind heavy end until proper balance is attained. See Figure

SAFETY WARNING

DISCONNECT THE SPARK PLUG WIRE AND PLACE THE BLADE CONTROL LEVER IN THE "OFF" POSITION.

1-48.

BENT BLADE Tilt the mower up on the knurfing bar and place a straightedge (yardstick) across the bottom of the pan. Rotate the blade until one end is aligned with the straightedge and measure the gap between the blade and the straightedge. Rotate the blade until the other end is under the same point of the straightedge and measure this gap. If the gaps are not within 1/4" of each. other, the blade should be replaced.

SAFETY WARNING

WHEN INSTALLING BLADE, MAKE SURE THE WASHER IS OVER THE SHOULDER ON THE SHAFT AND THE CONCAVE SIDE IS FACING THE BLADE. SEE FIGURE 1-49. TIGHTEN BLADE NUT SECURELY.

I I I 681717 FIGURE 1-48

I'

STIFFENER

I'

STIFFENER

BLADE

WASHER BLADE NUT

FIGURE 1-49

E N G I N E

The Riding Mower is powered by a 6 HP Briggs and Stratton engine. For information on the engine specs, adjustment data and maintenance procedures, refer to the manufacturer's service literature included with the owner manual.

Engine Removal. If it ever becomes necessary to remove the engine from the mower, use the following steps.

1. Remove the blade drive belt as described in BELT REPLACEMENT.

2. Disconnect the throttle linkage at the engine. See Figure 1-50.

3. Remove the four bolts and nuts securing 4. Install the engine in reverse order of re-

moval. 'Adjust the throttle linkage as the engine to the rear housing, and lift described i n manufacturer's literature the engine off the mower. included with owner manual.


SECTION 1 TROUBLESHOOTING

STEERING PROBLEMS

PROBLEM

Hard Steering

CAUSE

Low Tire Pressure

Lack of Lubricant

Bearings and/or Bushings worn

Tie Rods Bent

Steering Gear Broken

MOWER PAN AND BLADE PROBLEMS

PROBLEM CAUSE

Blade Won't Turn Belt Off Pulleys

Belt Damaged

Blade Nut Loose

Blade Won't Disengage

Blade Leaves Swirl Marks in Lawn

REMEDY

Check Pressure Chapter I1 Section 1

Lubricate Chapter I1 Section 1

Steering Disassembly and Inspection Chapter I1 Section 2

Straighten or Replace Chapter I1 Section 2

Disassembly and Replacement Chapter I1 Section 2

Blade Brake Not Working

Pan Unlevel

Blade Unlevel or Bent

REMEDY

Replace Chapter I1 Section 3


Tighten Chapter 11 Section 1 Refer to Spec. Sheet -- Torque

Check Blade Brake Tension Chapter I1 Section 3

Correct Pan Level Chapter I1 Section 3

Correct Pan Level Chapter I1 Section 3

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

MOWER .PAN AND BLADE Cont.

PROBLEM

Belt Comes Off (Rear)

Belt Comes Off (Front)

CAUSE

Belt Keeper Loose

Broken Belt

*Top Idler Pulley Broken or Bent

*Intermediate Shaft Loose

Rear Idler Spring Broken

Rear Idler Arm Broken

Broken Belt

*Bottom Idler Pulley Broken or Bent

*Intermediate Shaft Loose

Idler Arm Broken or Bent

Belt Pulley Bent or Broken

REMEDY

Tighten Chapter I1 Section 3







Replace Chapter 11 Section 3




*Diagram shown only.

DRIVE PROBLEMS'

I PROBLEM

Mower Will Not Propel

CAUSE

Improper drive adjustment

Drive Disc Polished

Drive Disc Broken

REMEDY

Adjust Chapter I1 Section 4

Score Chapter I1 Section 4

Repair o r Replace, Chapter I1 Section 4

11-18 SERVICEBULLETINREFERENCES REVISED 1977

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

PROBLEM

Mower Will Not Propel Cont.

DRIVE PROBLEMS Cont.

CAUSE

Rubber Drive Roller Worn o r Damaged

Chain Loose

Chain Broken

Transmission Rod(s) Bent

Differential Broken

Sprocket Worn or Broken

Wil l Not Drive In Reverse

Clutch Pedal Must Be Pulled Back for More Drive

REMEDY


Adjust Chapter I1 Section 4





Check Reverse Booster Spring o r Disc. Compression Spring Chapter II Section 4

Disc Compression Spring Adjust Chapter II Section 4

The following check list will assist in locating the problem source.

FUEL PROBLEMS

FUEL TROUBLE SHOOTING

TROUBLES REMEDIES CAUSES

Engine will not start a. Fill tank a. Fuel tank empty

b. Water in fuel b. Drain fuel from tank and

fresh fuel carburetor and replace with

c. Old fuel in tank forms

d. Shut-off valve closed

clean out fuel line gum to plug up fuel line c. Empty out old fuel and

d. Open valve

MODELS 9301, 9302, 9302E, 9303E, '9600, 9601 ONLY

FUEL PROBLEMS Cont. ~-

TROUBLES REMEDIES CAUSES

Engine slows down a. Unplug hole a. Vent hole in fuel tank and stops cap plugged

b. Fuel line or strainer

c. Refill tank c. Fuel tank runs dry

strainer clogged i b. Clean out fuel line or

IGNITION PROBLEMS

SPARK PLUG TROUBLE CHART

PLUG CONDITION

Black carbon or sooty deposit

Pitted o r burned points, white, light tan or blistered deposits. Rapid wear of points

Cracked or broken Plug

Cracked or broken insulator on lower end of plug

Widening of gap

CAUSES

a. Breaker points dirty or out of adjustment

b. Weak condenser

c. Incorrect plug

a. Incorrect plug

a. Careless installation of Plug

a. Center electrode strained when regapping Plug

a. Normal wear

RECOMMENDATION

a. Clean and adjust gap

b. Check and replace if weak

C. Install correct plug

a. Install correct plug

I-

a. Replace plug

a. Replace plug

a. Clean and regap

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

SPECIFICATIONS

LUBRICATION SPECIFICATIONS Grease For Front Axle & King Pin Spindle Boy “A” Grease or

Multiple Purpose, Automotive Grease

Multiple purpoSe, Automotive Grease Differential Lawn-Boy “A” Grease or

Multiple purpoSe, Automotive Grease

Front Wheel Bearings Lawn-Boy “A” Grease or

Hexshaft Drive Roller #30 Weight Oil

BOLT AND N U T TORQUES

King Pin to Tie Rod Nuts 135 inch pounds Steering Casting Bolts. 135 inch pounds

Engine Mounting Bolts. 135 inch pounds Engine Pulley Bolt 250 inch pounds Drive Disc Screws 90 inch pounds Belt Pulley Nut. 250 inch pounds Blade Nut 600 inch pounds Drive Roller Nuts 90 inch pounds

Wheel Bearing Bolts 175 inch pounds Differential Bolts 135 inch pounds Wheel Nuts Adjustable

Steering Gear Set Screw 135 inch pounds

Hexshaft Bearing Retainer Plate Screws 35 inch pounds

ENGINE SPECIFICATIONS

26” 30”

Idle r.p.m. 1,750 1,750 Operating r.p.m. 3,650 3,650 Oil Requirements SAE 10W/30 SAE 10W/30 Gas Tank Capacity 2 Qt. 2 Qt. Spark Plugs #‘s Champion CJ-8 Champion CJ-8

or Autolite A7N or Autolite A7N


MODELS 9301, 9302, 9302E, 9303E, ;9600, 9601 ONLY

TIRE SPECIFICATIONS

Front Size. 4.10/3.50~4 10x5/4.50-4 Pressure 15-17 P.S.I. 15-17 P.S.I. Rear Size 480/400x8 16~5.50-8 Pressure 22-25 P.S.I. 22-25 P.S.I.

BATTERY SPECIFICATIONS

Capacity Electrolyte Approximately 2 quarts Ampere Hour 24 Charging Rate 3 amp


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

SECTION 2

HOW TO REPAIR AND REPLACE

STEERING To insure trouble-free operation, use a grease gun and apply a good quality automotive chassis lubricant to the five zerk fittings. (Figure 2-1). Or Lawn-Boy “A” grease.

A positive type steering system is employed. The steering arm is keyed to the steering shaft and secured with a setscrew. The steering gear is linked to the left side spindle and king pin arm. A tie rod connects the wheels.

As you disassemble the front end, watch for bent or mis-shaped rods, dry bearings, bearings or bushings which are damaged, and shafts which are gouged or grooved.

FIGURE 2-1


MODELS 9301, 9302, 9302E, 9303E, i9600, 9601 ONLY

FIGURE 2-3 04238


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY STEERING DISASSEMBLY

FIGURE 2-4 RIGHT 94193

SPINDLE A N D / O R KING PIN REMOVAL

Disconnect the spark plug lead. Remove the battery, (electric start models only.) Stand mower on tilt (knurfing) bar. Remove front wheel. Remove tie rods from king pin arm. Drive out roll pin. Remove spindle from steering casting. See Figures 2-3 and 2-4.

NOTE

King pin a rms a re not identical (Fig- ure 2-4). Care should be taken to reinstall them properly.

FRONT AXLE REMOVAL Disconnect the spark plug lead. Remove the battery (electric start models only.) Stand mower on tilt (knurfing) bar. Remove spindle and king pin. (See spindle and/or king pin removal above.) Remove snap ring from pivot pin. Drive pivot pin from steering casting and axle. Remove axle. STEERING CASTING REMOVAL Disconnect spark plug lead. Remove battery, (electric start models only.) Stand mower on tilt (knurfing) bar. Remove front axle. Remove steering wheel and pedal support rod. Remove two bolts securing steering casting to main frame casting. Remove steering casting from main frame.

CORRECT

04267 FIGURE 2-5A

RIBS IN

I

INCORRECT FIGURE 2-5B

04268

IMPORTANT NOTE: Later model bushings contain two ridges which match the grooves in the frame castings. During reassembly the bushings MUST BE placed in the same position they were removed to prevent binding of the steering shaft. See Figures 2-5A and 2-5B. Loosen the setscrew on the pitman arm. Using expansion pliers remove the retaining ring and remove pitman arm.

STEERING CASTING DISASSEMBLY Disconnect spark plug lead. Remove battery, (electric start models only.) Stand mower on tilt (knurfing) bar. Remove steering casting. Remove all bolts holding casting together. Casting halves can then be separated (Figure 2-5). Pull steering shaft from casting. Note plastic bushings a r e ribbed for placement in casting--do not clean with solvent. The steering gear is held to the steering shaft with a retainer ring and a setscrew.

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

FIGURE 2-6 94173

\

STEERING WHEEL ALIGNMENT !

If steering wheel does not line up properly 2. Loosen ,jam nut at ball joint socket and with front wheels, it can be aligned as turn ball joint on o r off rod until steering follows: wheel is aligned with front wheels. (Fig-

ure 2-6.j

1. Remove nut securing ball joint to king 3. Assemble ball joint to king pin a rm and pin arm. tighten nut.

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

SECTION 3

ADJUSTMENTS

POWER FOR DRIVING

To effect transmission of motive power to the cutting blade, two V-belts a r e used.

The primary drive pulley which is located above the drive disc is keyed to the engine crankshaft. A short V-belt runs from this primary pulley to the upper pulley on the intermediate spindle. A' longer V-belt connects the lower pulley on the intermediate spindle to the blade pulley on the blade shaft, driving the cutting blade.

THE MOWER BLADE

Two idler pulleys are used in the blade drive system as illustrated below. A blade brake applied to the short belt (rear) stops the blade. The brake is applied by the control lever.

As .the mower pan is disassembled, examine rods and suspension assembly for damage or distortion, for bent o r misshapened rods, bearings or bushings which a re damaged o r worn, dry bearings, and shafts which are gouged or ringed.

FIGURE

PRIMARY BLADE DRIVE IDLER BLADE

PULLEY PULLEY BELT

DRIVE INTERMEDIATE IDLER DISC DUAL PULLEY PULLEY

AND SPINDLE 2-7 94311


04242


MODELS 9301, 9302, 9302E, 9303E. 9600, 9601 ONLY MOWER PAN DISASSEMBLY

I 1

REAR BELT REMOVAL

Disconnect spark plug lead. Remove battery, (electric start models only). Remove rear cover. Remove belt keeper (Figure 2-11); tighten tilt (knurfing) bar bolts. Stand mower on tilt (knurfing) bar.

SAFETY WARNING

SECURE TO WALL TO PREVENT THE MOWER FROM TIPPING OR FALLING.

Roll belt off the top intermediate pulley. Pull belt between drive disc and drive roller.

Reassemble in reverse order of disassembly.

PAN REMOVAL

Remove belt, and bell arm shoulder bolts. Remove front pan suspension bar shoulder bolts. Pan can now be removed from mower.

FRONT BELT REMOVAL Disconnect spark plug lead.

NOTE

Use a rope as shown on Figure 2-10 when removing idler spring.

Remove belt.

Reassemble in reverse order of disassembly.

IDLER ARM REMOVAL FIGURE 2-11 94181 ~-

Remove belt. Remove belt pulley. Remove and replace idler arm. (See Figure 2-9.)


MODELS 9301, 9302, 9302E, 9303E, '9600, 9601 ONLY BLADE BRAKE ADJUSTMENT

When the blade control lever is placed in SAFETY WARNING the “off” position, an adjustable leaf spring connected to the bell a rm and hub assembly is forced against the drive belt preventing the blade from rotating.

BLADE NUT MUST BE TIGHT BE- FORE ADJUSTING BLADE BRAKE TENSION. SECURE MOWER TO PREVENT TIPPING OR FALLING.

The blade brake leaf spring be ad- 1. Use a right angle screwdriver to loosen justed to obtain blade stoppage in not less than (4) four or more than (6) six seconds with engine operating at 3600 RPM.

the lock screw on the blade brake leaf spring. See Figure 2-12.

To obtain proper blade brake tension: 2. Move the spring in or out until desired position, is obtained.

Disconnect spark Plug lead- Remove bat- 3. Tighten lock Screw Lower tery, (electric start models only.) mower back on wheels. Stand mower on tilt (knurfing) bar. 4. Start engine, letting it run about (2) two

minutes' to warm up.

5. Place blade control lever in "off" position. Check blade stoppage by visually observing drive pulley. DO NOT place

FIGURE 2-12 94184


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY PAN TILT ADJUSTMENT- 26” & 30’’ MODELS

1. Locate the mower on a flat level surface such as a driveway, sidewalk, garage floor, etc.

2. Place the height adjustment lever in the middle setting.

3. Rotate the blade until the cutting edge is facing the front of the mower and measure the distance from the ground to the tip of the cutting edge of the blade. See Figure 2- 13.

4. Rotate the blade 180º and measure (from rear of pan) the distance’ from the ground

to the tip of the cutting edge of the blade. See Figure 2-13.

5. The mower pan tilt is Correct if the measurement obtained in step 4 is 1/4 inch higher than the measurement obtained in step 3.

6. The pan tilt may be adjusted by removing the cotter pin on one end of the tilt adjust rod, loosen the jam nut on the clevis and turn the rod in o r out of the clevis until the required tilt is reached. Secure clevis with jam nut. See Figure 2-14.

7. See page 11-54 and check for bent blade.

FIGURE 2-14 94276

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

SECTION 4 THEORY OF OPERATION

INTRODUCTION The Lawn-Boy Riding Mower is powered by a vertical shaft four-cycle gasoline engine mounted on the rear of the machine. The vertical crankshaft of the engine drives both the wheels and the cutting blade, with the speed of the forward motion determined by the Speed Selector Lever which provides three forward speeds, a reverse, and a neutral position. The speed of the cutting blade on the mower is determined by the revolutions per minute of the engine. The throttle allows varying speeds of the engine up to a maximum of 3600 rpm.

Because of the selective controls of the Rider, it is possible to drive the machine without the cutting blade rotating, to drive the wheels slowly while the cutting blade and engine are at full 3600 rpm for maximum cutting in heavy growth, and to regulate from the driver's seat many combinations of speed and cutting heights.

FIRST POSITION

FIGURE 2-15

94316

POWER FOR DRIVING THE WHEELS

The driving of the wheels is accomplished through the use of a large aluminum drive disc which is keyed to the vertical crankshaft of the engine. Because this disc always rotates at the speed of the engine, transfer of motive power at varying speeds is accomplished through the use of linkages, by bringing the rubber-tired drive roller into contact with the disc at three different positions from the center of the disc. The linear speed of any point on a wheel is highest when the point is at the rim and slowest at the hub. The first position

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

shown, Figure 2-15, is nearest the center and is the slowest speed, or First. The second position shown, Figure 2-16, produces a higher speed, o r Second, and the third position, Figure 2-17, near the rim of the disc produces the highest speed, or Third. In third position, the Rider will travel at approximately 6 mph. It is also characteristic of a rotating disc to transmit power in either direction, depending upon which side of the disc is brought into contact with the drive roller. The drive roller is shown, Figure 2-18, in contact with the disc on the opposite side of center. Note that the drive roller is quite close to the center for low-

' , drive roller is not in contact with speed, safe backing. In neutral position, Figure 2-19, the the drive disc.

SECOND POSITION

FIGURE 2-16

\

94317

The use of the large aluminum driving disc and the rubber-tired drive roller offer an ad- vantage in that power can be transmitted to the wheel and speeds changed without the use of a clutch. The drive roller slides smoothly across the face of the turning disc, making i t easy to start, change speeds, or go into reverse without clutching. The Rider does, however, provide a clutch to prevent engine choking out during sudden stops when it is not possible to shift the speed selector, and when parking the machine and shifting into gear when the engine is not running. Depressing the clutch lifts the drive roller from contact with the disc and prevents damage to the drive roller as it passes across the motionless driving disc.


MODELS 9301, 9302, 9302E, 9303E,' 9600, 9601 ONLY

Inherent in the driving system of disc and drive roller making sudden contact is a tendency to lurch or buck when the machine is started from a dead stop. To make smoother starts possible, a series of sprockets and chains transmits the motive power from the drive roller to the wheels. In Figure 2-20 is shown the smooth transmission of power as the sprocket on the drive roller shaft turns a primary chain connected to the sprocket on the intermediate

REVERSE POSITION

FIGURE 2-18

11-34 REVISED 1977


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

driveshaft. The sprocket on that shaft, in turn drives an intermediate chain which drives a sprocket on the final drive spindle. The dual sprocket on the final drive spindle drives a final drive chain on the big sprocket mounted on the wheel axle to move the wheels. This combination of sprockets and chains reduces starting torque and absorbs the shock and lurching of starting.

94311


MODELS 9301, 9302, 9302E, 9303E, '9600, 9601 ONLY

To eliminate drive roller slippage and to assure smooth starts, a system of two disc compression springs is employed. When the speed selector lever is placed in gear, the primary disc compression spring creates initial drive roller pressure against the drive disc. Momentarily, the drive roller is allowed to slip, eliminating quick "jumpy" starts. The secondary disc compression spring then goes into effect supplying additional disc pressure to propel the unit. (See Figure 2-21.)

FIGURE 2-21 i-

n NOTE 9301, 9302, 9302E 9600 have a single disc compression spring; 5 inch roller. Theory is the same.

MODELS 9302, 9302E, 9303E, 9600, 9601 ONLY

NOTE

CHAIN TENSIONER 9303. 9303E, 9601

COMPRESSION SECONDARY


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY PRIMARY DRIVE SERVICING

DISC COMPRESSION SPRING REMOVAL

Disconnect spark plug lead; remove battery, (electric start models only). Remove rear cover.

Remove both disc compression springs.

Models 9301, 9302, 93023, and 9600 have single disc compression spring.

The springs are not identical--tag one as inside; the other a s outside. Remove the springs with a rope. (See Figure 2-24.)

RUBBER DRIVE ROLLER SERVICE

Disconnect spark plug lead; remove battery, (electric start models only,) stand mower on tilt (knurfing) bar.

Remove chain tensioner on primary drive chain. (See Figure 2-22.) There will be enough slack to lift the chain off the hexshaft sprocket.

Place speed selector in reverse. Remove four nuts securing drive roller to roller hub. Remove the two screws securing hexshaft bearing retainer plate and remove hexshaft and bearing.

_-

Before reinstalling drive roller, wash felt wick and apply a small amount of petroleum jelly to it (Figure 2-25.) Periodic inspection of the rubber roller and periodic lubrication of the felt oiler pad on the drive roller are the only regular maintenance operations on the drive roller. The rubber portion of the drive roller may crack, chip, or wear, but will be satisfactory as long as there are no large pieces broken out.

After reassembly, adjust the drive roller. See Drive Roller Adjustment.

FIGURE 2-25

11-38 e . e . . . . . e . . . . . . . . a s . SERVICE BULLETIN REFERENCES REVISED 1977

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY DRIVE ASSEMBLY ADJUSTMENTS

DRIVE ROLLER TRAVEL HORIZONTAL

Disconnect spark plug lead; remove battery, (electric start models only,) stand mower on tilt (knurfing) bar.

The cast iron bearing carrier of the drive roller assembly must be in contact with the extended threaded ends of the screws holding the hex shaft bearing retainers to the drive bracket with the shift lever placed in the full reverse position (Figure 2-26.) This will allow the drive roller to move across the face of the drive disc as the operator shifts through the three forward speeds or reverse. The drive roller must be readjusted whenever a new roller is installed. To obtain the correct adjustment proceed as follows:

1. Place speed selector lever in "reverse." Loosen jam nut on speed control rod. (Figure 2-26.)

2. Remove nut securing ball joint stud to bell arm assembly.

3. Turn ball joint onto the rod to lengthen travel--off rod to shorten travel (Figure 2-26.) Proper adjustment does not necessarily put the drive roller on center line of drive disc when shift lever is in neutral.

4. When proper adjustment is made, attach ball joint to the bell arm assembly and tighten nut securely. Tighten jam nut up against the ball socket.

5. This is necessary to retain correct rear speed.

Inspect the drive disc closely. If the surface is polished the rubber drive roller will slip. Remove polish finish by rubbing in a circular pattern with sand paper or emery cloth.

681902 FIGURE 2-26 94331


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

FIGURE 2-27 94332

DRIVE ROLLER ADJUSTMENT- VERTICAL ALIGNMENT When the speed selector lever is placed in neutral position, the drive roller disengages from the drive disc by use of various linkages. Proper clearance between drive disc and drive roller is 1/16 inch with speed selector lever in neutral. See Figure 2-27. This assures the operator of a positive neutral position and performs a secondary braking action by halting the chain movement to the rear wheels.

To obtain the proper 1/16 inch clearance proceed as follows: 1. Place speed selector lever in neutral

position.

2. Stand mower on knurfing bar to make adjustment.

See page 11-41 for steps 3, 4, and 5 for models 9301, 9302, 9302E, 9600. See page 11-42 for steps 3, 4, and 5 for models 9303, 9303E, 9601.

11-40 SERVICE BULLETIN REFERENCES REVISED

MODELS 9301, 9302, 9302E, 9600 ONLY

MODELS 9303, 9303E, 9601, ONLY

3. Tighten upper reverse booster spring nut until spring is compressed 1 1/2". See Figure 2-30.

4. Tighten or loosen upper nut on, speed control clutch rod to obtain 1/16 inch clearance between roller and disc.

5. Tighten remaining jam nuts.


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY DRIVE ROLLER ADJUSTMENT- SPRING TENSION

A. Primary (inside) Disc Compression lbs., pressure and the drive roller Spring Adjustment breaks contact with the drive disc.

1. Place mower in horizontal position and remove rear cover.

2. Place speed selector lever in second gear. Do not depress clutch pedal.

3. Remove secondary (outside) spring.

4. Attach spring scale to hex shaft. While pulling downward on scale, rotate primary (inside) adjustable eccen- tr ic until spring scale reads 4 to 5

See Figure 2-31.

5. Replace secondary disc compression spring.

B. Secondary (Outside) Disc Compression Spring Adjustment (Figure 2-32).

1. Attach spring scale to hex shaft. While pulling downward on scale rotate secondary (outside) adjustable eccentric until the spring scale reads

FIGURE 2-31 24300


MODELS 9301, 9302, 9302E, 9303E, i9600, 9601 ONLY

15 to 17 lbs., pressure and the drive roller breaks contact with the drive disc.

2. Place speed selector lever in neutral position and re-check the 1/16 inch clearance between drive disc and, drive roller.

NOTE

If drive roller slippage is observed, slightly increase the spring tension on the secondary (outside) spring. If quick "jumpy" starts are observed, decrease spring tension on the primary (inside) spring.

FIGURE 2-32 04299

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

BRAKE ROD\

BRAKE BAND.

14076

BRAKE'DRUM INTERMEDIATE SHAFT' FIGURE 2-33

ROLL PINS

PRIMARY CHAIN SECONDARY-

CHAIN

SPROCKET

ASSY MODELS

INTERMEDIATE SHAFT

FIGURE 2-34 0425


MODELS 9301, 9302, 9302E, 9303E, '9600, 9601 ONLY

SECONDARY .DRIVE SERVICING

Remove brake band from chasis. Remove secondary chain (Figure 2-35.)

Remove bearing retainer plates from chasis. Remove bearings and driveshaft.

Replace intermediate driveshaft and reassemble in reverse order of disassembly.

Loosen nylon chain guide eccentric nut slightly and rotate into or away from chain to attain proper chain tension. Correct chain tension is 1/4 inch deflection with light thumb pressure.

WHEEL BRAKE ADJUSTMENT

The friction type brake system consists of a foot pedal, brake rod, brake and drum assembly. A s foot brake is depressed, a reinforced band on brake assembly is forced against the drum. This action brakes the intermediate drive, thus stopping wheel rotation. To prevent damage to the drive roller, the clutch and brake must be applied

simultaneously when making a stop. To adjust brake proceed a s follows:

1. Remove' cotter pin and washers from the brake rod at foot pedal. (Figure 2-36) and remove rod.

2. Loosen jam nuts at turnbuckle. See (Fig- ure 2-37). Screw brake rod in o r out of turnbuckle for proper adjustment which is obtained when slight pressure on the pedal encounters resistance after 1/2 inch pedal travel.

3. Tighten, jam nuts at turnbuckle and reassemble brake rod to the foot pedal.

MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

FIGURE 2-38 1 A 0 7 9

FIGURE 2-39 04247

MODELS 9301, 9302, 9302E, 9303E, ‘9600, 9601 ONLY FINAL DRIVE DISASSEMBLY

DIFFERENTIAL REMOVAL Disconnect spark plug lead; remove battery (electric start models only).

SAFETY WARNING




Stand mower on tilt (knurfing) bar. Remove rear belt. !

Remove rods from carrier bracket and disc compression springs. Lower bracket to floor.

Remove chain, rear wheels and axle bearings.

Place blade control lever in “on” position and slide differential out.

NOTE

Be careful not to mar the drive disc with the differential sprocket teeth when removing the differential.

Reassemble in reverse order of disassembly. After reassembly place blade control lever in off position.

DIFFERENTIAL DISASSEMBLY Remove differential. (See above.)

Remove four bolts holding differential and sprocket together. Differential halves can then be separated. Inspect parts, etc., (Fig- ure 2-39.

When reassembling, pack differential with 3 ounces of Lawn-Boy “A” grease/


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

ENGINE REMOVAL Disconnect spark plug lead and throttle linkage. Remove rear drive belt.

For Model 9601 also remove 2 cylinder head bolts attached to support mounting plate (Figure 2-40.)

Remove engine mounting bolts and lift engine from mounting frame.

NOTE

Do not tip engine on its side without removing oil and fuel.

DRIVE DISC REMOVAL

Remove engine. Remove four allen head screws securing disc to drive pulley.

DRIVE PULLEY REMOVAL

Remove engine and drive disc. Remove single bolt securing drive pulley to keyed crankshaft and remove pulley.


MODELS 9302E, 9303E ONLY

SECTION 5

ELECTRICAL SERVICING

FIGURE 2-41 L

Follow these procedures to remove battery.

1. Remove two wing screws and remove battery cover.

2. Disconnect battery leads.

3. Remove four nuts securing battery carrier to battery frame and remove battery. See Figure 2-41.

SAFETY WARNING

DO NOT ALLOW BATTERY TERMINALS TO MAKE CONTACT WITH THE BATTERY FRAME. THIS

SONAL INJURY (BURNS). SEE COULD RESULT IN FIRE OR PER-

FIGURE 2-42.


MODELS 9302E, 9303E ONLY

DIODE I GROOVED END

DIODE

FIGURE 2-43 FRONT OF MOWER 94256

INSTALLING NEW DIODES

1. Remove diode cover.

2. Insert new diodes into spring clips. DO NOT FORCE. The groove in the one end of the diode matches a ridge in the clip. See Figure 2-43.

INSTALLING REPLACEMENT FUSE AG AMP 250 Volt Fuse is inserted into clip receptacle in vertical position either end up.

SAFETY WARNING

SONAL INJURY (BURNS) REMOVE TO PREVENT SPARKS OR PER-

DIODES IF MOWER IS TO BE OP- ERATED WITH BATTERY RE- MOVED OR BATTERY LEADS DIS- CONNECTED.


MODELS 9301, 9302, 9302E, 9303E, 9600, 9601 ONLY

SECTION 6

PREVENTIVE MAINTENANCE

To obtain peak performance and long life from the engine the air cleaner must be serviced regularly. Under normal conditions an air cleaner should be serviced every 10 hours of operation, oftener, if under dusty condition. To service air cleaner, pour old oil from bowl. Wash element thoroughly in solvent and dry. Clean bowl and refill with same type of oil used in crankcase. See engine Owner’s Manual.

CRANKCASE O I L

TIRES

Recommended pressure for front wheels on Models 9601, 9303, 93033 is 15-17 lbs. Rear pressure for the same models is 22- 25 lbs.

BATTERY

Check battery fluid level every 10 hours of operation.

Add distilled water to f i l l ring.

BLADE CARE

A blade will naturally become dull with use. It can be quickly sharpened with a few strokes of a file or sharpening stone. SHARPEN ONLY THE CUTTING EDGE. A blade that is not straight or properly balanced can cause engine vibration; loss of engine power. Excessive vibration can lead to engine (usually crankshaft) damage if allowed to continue. Imbalance can be caused by uneven wear o r impact damage. Minor imbalance can usually be corrected by grinding or filing the heavy end; if not, the blade should be replaced.

gravity of battery falls below- 12.25, recharge battery.

In storage; Battery should be charged fully once per month.

SAFETY WARNING

DO NOT CHARGE AT A RATE EX- CEEDING 4 AMPS.

DO NOT allow tools to make contact with the battery terminals when installing or servicing battery.

Remove diodes if mower engine is to be operated with’ battery removed o r battery leads disconnected.

DO NOT tip mower up on tilt (knurfing) LUBRICATION

A. Lubricate front wheel bearings with Automo- bar without removing battery. tive Chassis Lubricant or Lawn-Boy “A” Grease. Using conventional grease gun apply lubricant DO NOT operate mower with battery cover until grease is observed at end of the bearing removed. surface.

B. Lubricate friction points whenever DIFFERENTIAL needed. All bushings are oil impregnated and do not require oil.’ All ball bearings Check differential every 50 hours. Fill to are sealed with lubricant and therefore do 3 ounce capacity with multi-purpose auto- not require periodic lubrication. motive grease.


MODELS 9301, 9302, 9302E, -9303E, 9600, 9601 ONLY

FRICTION DRIVE

Check rubber drive roller drive disc clearance every 30 hours.

BLADE

SAFETY WARNING

DISCONNECT THE SPARK PLUG WIRE AND PLACE THE BLADE CONTROL LEVER IN THE "OFF" POSITION.

Always keep blade sharp and balanced. A bent blade will cause vibration and loss of power. See Figure 2-44. Check balance and grind heavy end until proper balance is at-

FIGURE 2-44 681717

BLADE REMOVAL

1. Disconnect spark plug.

2. Lift mower on end.

3. Block blade with a piece of 2 x 4 to prevent it's turning. Figure 2-45.

4. Remove blade nut.

5. Retorque blade nut to 50 ft. lbs.

MODELS 9301, 9302, 9303E, 9600, 9601 ONLY 9302E,

BENT BLADE

Tilt the mower up on the knurfing bar and place a straightedge (yardstick) across the bottom of the pan. Rotate the blade until one end is aligned with the straightedge and measure the gap between the blade and the straightedge. Rotate the blade until the other end is under the same point of the straightedge and measure this gap. If the gaps are not within 1/4” of each other, the blade, blade spindle, blade adaptor or deck may be damaged or distorted. Remove blade and place on flat surface. If blade tips are not within 1/4” replace.

SAFETY WARNING

WHEN INSTALLING THE BLADE

STALLED IN THE CORRECT SE- QUENCE IN WHICH THEY WERE

TIGHTEN BLADE NUT SECURELY

ING LOOSE.

MAKE SURE ALL PARTS ARE :IN-

REMOVED. SEE FIGURE 2-46.

TO PREVENT BLADE FROM COM-

CHAPTER 111 MODELS 9500, 9501 ONLY

SECTION 1

INTRODUCTION

Models 9500 and 9501 Lawn-Boy compact riders are propelled by a conventional, geared transmission with two forward speeds and one reverse. The maximum speed in second gear is 3.6 mph. In first gear and reverse the maximum speed attained is 2.2 mph.

A 5 h.p. recoil start Briggs and Stratton 4 cycle engine with a maximum rpm range of from 3400 rpm to 3600 rpm powers the Mower. For service see an authorized Briggs and Stratton dealer.

A unique feature is the aircraft-type steering which offers ease and comfort to the operator.

The 26 inch floating pan may be adjusted to 5 different cutting positions between 1-1/2 inches and 3-1/2 inches. The front wheels are semi-pneumatic while the rear t ires are fully pneumatic and maintain 30-35 pounds air pressure.

The front axle is full floating and the main frame is of tube type to provide maximum strength.

The overall length is 55-1/2" and 28-3/16" wide.

SERVICE BULLETIN REFERENCES . 11-55 REVISED 1977

MODELS 9500, 9501 ONLY

SECTION 2

SPECIFICATIONS

ENGINE Idle rpm. 1800 rpm's Operating rpm 3400 3600 rpm's maximum Oil requirement SAE 30 Wt. service MS Crankcase capacity 2 pints Spark plug Champion CJ8-Autolite A7N

TIRE SPECIFICATIONS Front size 10 x 3.50 semi-pneumatic Rear size. .13 x 5.00-6

Pressure 30-35 PSI

SECTION 3 LUBRICATION

I

I LAWN-BOY "A" GREASE NOTE I OR EQUIVALENT Care must be taken not to allow oil

to come in contact with brake band 1. Lubricate both front wheels at zerk lining at transmission or friction

fittings. material on blade stop.

2. Lubricate rear axle bearings at zerk PETROLEUM JELLY fittings (2 places).

SAE #30 OIL 1. Felt washers rear wheels liberally

coat.

1. All six pivot points in the mower pan suspension linkage. LAWN-BOY "A" GREASE

2. Rod end and ball joints.

3. Mower engagement lever pivot.

1. Bell arms Foot pedal liberally coat i.d. of boss on frame castings and rod- foot rest.

4. Transmission clutch mechanism. 2. Pivot pin front axle fill reservoir.

5. Blade clutch mechanism.

6. Axle pan wheels.

3. Pivot pin on bell arm and pin assembly transmission clutch idler liberally coat pin.

Front axle king 4. voirs (2 places).

TRANSMISSION

MODELS 9500,

pin bores - fill reser-

12 oz. of Shell "Darina Ax" grease or equivalent evenly distributed within transmission and on camplate.

9501 ONLY

DIFFERENTIAL

.75 to 1.25 ounces of Shell Expro 71030 grease or equivalent. The thrusting area of each gear and shaft bearing surfaces should be greased.

SECTION 4

HARDWARE TORQUES

Torque to values given for thread size unless listed separately.

THREAD SIZE 10 - 32 1/4 - 20 5/16 18 5/16 - 24 3/8 - 16 3/8 - 24

DESCRIPTION

Screw - chain guard Screw - mower pan brackets to pan Nut - "U" bolt to frame Nut - Trans idler pulley to idler arm Bolt Seat Nut Mower wheel axle to pan bracket Nut wheel spindle to axle Nut pivot mower pan suspension Nut blade Screw transmission case halves Screw transmission cover plate Screw transmission shift forks

TORQUE 35 to 38 inch lbs. 63 to 75 inch lbs. 142 to 170 inch lbs. 142 to 170 inch lbs. 190 to 225 inch lbs. 235 to 280 inch lbs.

TORQUE

45 to 59 inch lbs. 91 to 119 inch lbs. 91 to 119 inch lbs. 149 to 195 inch lbs. 355 to 465 inch lbs. 355 to 465 inch lbs. 195 to 255 inch lbs. 372 to 487 inch lbs. 459 to 600 inch lbs. 70 to 80 inch lbs. 20 to 25 inch lbs. 35 to 45 inch lbs.


MODELS 9500, 9501 ONLY SECTION 5

TROUBLESHOOTING STEERING

I PROBLEM CAUSE I Hard steering Lack of lubricant

Bearings and/or bushings worn Tie rods bent Steering arm broken

Blade won't turn

Blade won't disengage

Blade leaves swirl marks in lawn

Blade belt comes off (Rear)

Blade belt comes off (Front)

REMEDY

Lubrication Section 3 Steering disassembly and inspection Section 6 Straighten or replace Section 6 Disassembly and replacement Section 6

BLADE HOUSING AND BLADE Belt off pulleys Belt damaged Blade nut loose Seized bearings Blade adapter broken

Blade brake not working Blade control mecha-

nism broken

Housing unlevel

Blade unlevel or bent

Belt keeper loose

Broken belt Top idler pulley broken o r bent Pulley shaft loose Rear idler spring broken Rear idler arm broken or bent

Broken belt

Bottom idler pulley broken o r bent Intermediate pulley shaft loose Idler arm broken or bent Engine belt pulley bent or broken

Replace Section 7 Replace Section 7 Tighten Section 7 Refer to Spec. Sheet Torque

Check blade brake spring

Correct housing level Section 7

Replace blade Section 7

Adjust and tighten

Replace Replace

Tighten Replace

Replace

Replace

Replace

Tighten

Replace

Replace



DRIVE PROBLEMS PROBLEM

Mower will not propel

Engine will not start

Engine slows down and stops

Black carbon o r sooty deposit

Pitted or burned electrodes, white, light tan o r blistered deposits. Rapid wear of electrode

Cracked o r broken

Cracked o r broken insulator on lower end of plug

Widening of gap

Plug

CAUSE

Chain loose Chain broken

Differential broken Sprocket worn o r broken Drive belt broken o r damaged Transmission won't shift

FUEL TROUBLE

REMEDY

Adjust Repair or replace

Repair o r replace - Section 10 Replace Section 8

Replace Section 8

Repair Section 8

a. Fuel tank empty a. Fill tank b. Water in fuel

c. Old fuel in tank gums up tank, fuel line and carburetor

d. Shut-off valve closed a. Vent hole in fuel tank

b. Fuel line or strainer cap plugged

clogged

b. Drain fuel from tank and carburetor and replace with fresh fuel

c. Empty out old fuel and clean all parts involved

d. Open valve a. Unplug hole

b. Clean out fuel line or strainer

c. Fuel tank runs dry c. Refill tank

SPARK PLUG TROUBLE a. Breaker points dirty

o r out of adjustment b. Weak condenser

c. Incorrect plug a. Incorrect plug

_-

a. Careless installation of plug

a. Center electrode strained when regapping Plug

a. Normal wear



c. Install correct plug a. Install correct plug

a. Replace plug

a. Replace plug

a. Clean and regap


MODEL 9500 ONLY

FOOT REST ASSEMBLY

STEERING SHAFT AND ARM ASSEMBLY

PEDAL BELL

PEDAL AND FOOT REST SUPPORT ROD

AND STEERING

GREASE FITTING

FIGURE 3-1

MODEL 9501 ONLY

STEERING HANDLE

STEERING SHAFT AND ARM ASSEMBLY

FOOT REST ASSEMBLY

PEDALANDFOOT RESTSUPPORTROD

AND STEERING

GREASE FITTING

FIGURE 3-1 A


MODELS 9500, 9501 ONLY SECTION 6

FRONT END STEERING FRONT AXLE REMOVAL

The steering is positive type. The steering shaft controls front wheel movement thru a steering arm, tie bar and tie rod.

NOTE

During disassembly examine all parts for excessive wear or damage.

SPINDLE AND STEERING ARM REMOVAL Disconnect the spark plug lead; raise the front of the mower up resting it vertically on the rear cover and engine.

SAFETY WARNING

SECURE TO WALL OR OTHER

PING OR FALLING. FIXED OBJECT TO PREVENT TIP-

Disconnect spark plug lead; raise the front of the mOwer up resting vertically on the rear cover plate and engine.

SAFETY WARNING



Remove the wheels and spindle and steering arm assemblies.

Remove axle pivot pin retaining ring and pull pin from steering housing and slide axle out of steering housing.

Reassemble in reverse order.

Remove the wheel and disconnect tie rod Apply a liberal amount of Lawn-Boy “A” from the steering arm. Remove the steer- grease or Lubriplate 6 3 O A A lubricant to ing arm spindle nut on top of axle and pull pivot pin and other friction points. spindle and steering arm from axle housing.

Remove the upper and lower bearing and spacer, STEERING CASTING & STEERING and examine for wear. Apply a coating of Lawn- SHAFT REMOVAL Boy “A” grease or Lubriplate 6 3 O A A lubricant be- !

fore reinstalling. Reassemble in reverse order. Remove the front axle and steering handle, detach the steering tie bar ball joint ’from the steering arm, disconnect brake and clutch rod linkage at rear of unit. Remove pedal and foot rest support rod retainer ring from either side and drive rod out of foot rests, pedals and steering housing.

Remove the two (2) bolts securing the steering housing to the main frame and pull steering housing and control rods away from 3-2 main frame.

NOTE Remove the nuts from the bolts remaining in the steering housing, leaving the bolts in

The left and right hand spindle and place. Place the frame casting on the floor steering arms are not interchange- or work bench with the bolt heads down and able. separate halves of the housing to expose


MODELS 9500,

the steering shaft and arm assembly, nylon bushings and the two pedal bell a rm assemblies.

Thoroughly clean the inside of the housing halves with a suitable solvent. Do not wash or wipe nylon bushings with solvent. Apply Lawn-Boy “A” grease or Lubriplate 630AA lubricant to nylon bushings before reinstalling.

9501 ONLY

The nylon bushings include 2 ribs. When reinstalling, these ribs must be located in matching grooves in the steering casting halves. Figure 3-3.

FIGURE 3-3 ~---

SERVICE BULLETIN REFERENCES a e a a e a e a 11-63 REVISED 1977


STEERING WHEEL ALIGNMENT

If the steering wheel does not line up properly with the front wheels, it can be aligned a s follows:

1. Remove the nut securing ball joint to king pin arm.

2. Loosen the jam nut at the ball joint socket and turn the ball joint onto or off the rod, see Figure 3-4, until the steering wheel is aligned with the front wheels.

3. Check wheels for alignment.

4. Assemble the ball joint to the king pin arm and tighten the jam nut.

MODEL 9500 ILLUSTRATED FIGURE 3-4

During ‘assembly all moving parts and friction points such as bearings, bushings, and bolt threads should be lubricated with Lawn-Boy “A” grease or Lubriplate 620AA lubricant.

The front wheel bearing and axle must be lubricated every 25-30 hours of operation with either of the above mentioned lubricants. Note grease fitting in Figure 3-5.

MODEL 9500 ILLUSTRATED FIGURE 3-5 _- __I-


---


LINK

IDLER SPRING

B L A D E S P I N D L E

BRACKET BRACKET

RETAINING RING

BLADE HOUSING HOUSING

I WHEEL

14113

FIGURE 3-6 -I-



SECTION 7

BLADE DRIVE & BLADE HOUSING ASSY,

The cutting blade is driven by a system of V belts and pulleys.

The primary drive pulley is keyed to the engine crankshaft. A short 31-3/4 inch V belt runs from the primary pulley to the top pulley of the intermediate pulley and spindle assembly. The blade spindle pulley is in turn powered by a longer 48-3/8 inch belt driven by the bottom, pulley of the intermediate pulley and spindle assembly. These are specially designed belts for these specific applications. Standard "V" belts will not give satisfactory life.

Two idler pulleys are used in the blade drive system. One is located under the belt cover adjacent to the blade drive pulley; it is always engaged with the V belt.

The other idler is a part of a combination rear blade drive belt idler and blade brake assembly. It is located adjacent to the top pulley of the intermediate pulley and spindle assembly. It is actuated by the blade engagement lever. When it is in "on" position the idler pulley is engaged with the belt. When it is in "off" position a blade brake engages with the top pulley of the intermediate pulley assembly stopping the cutting blade within six (6) seconds.

BLADE PULLEY

I I

I

I

\ \ \ \ \

\ \ RETAINER \ \ \ \ \

\ PULLEY ='FRONT BELT

TOP VIEW FIGURE 3-7



BELT REPLACEMENT

FRONT BELT REAR BELT

Disconnect the spark plug lead and remove the belt cover. Slip a length of rope thru the eye of the belt idler spring and pull spring off hook to release tension. See Figure 3-8.

Disconnect spark plug lead; raise the front of the mower up resting it vertically on the rear cover and engine.

SAFETY WARNING

SECURE TO WALL OR OTHER FIXED OBJECT TO PREVENT TIP- PING OR FALLING.

Disconnect primary (rear) belt idler spring; loosen the belt keeper and roll the belt off the pulley system. Replace in reverse order.

BLADE HOUSING REMOVAL

Remove the front blade belt and remove retainer clip from either side of front pan support rod and slide rod out. Remove shoulder bolts from rear pan, link arms at pan and slide mower housing out from under mower chassis. Reassemble in reverse order.

BLADE PULLEY SPINDLE TO' BEARING REMOVAL Remove blade housing, blade, and blade adapter. Remove woodruff key from blade spindle and drive threaded end of spindle with a soft headed hammer (rubber or plastic) out of the spindle housing. Reas- semble in reverse order. To remove spindle bearing, remove bearing retaining ring inside lower end of spindle housing.

BLADE HOUSING HEIGHT (CUTTING) ADJUSTMENT

NOTE

After installation of belt, pin on belt keeper assembly must be positioned as pictured in Figure 3-9.

The cutting blade may be se t at five different heights, from 1-1/2 to 3-1/2 inches. To adjust, simply position the front pan support rod in the desired hole in the adjustment plate. The rear adjustment is made

Belt may now be removed. Replace in re- similarly by placing the rear wheel axle in verse order. the desired position in the adjustment plate.


MODEL 9500 ONLY

SEAT

FRAME

REAR BLADE TRANSMISSION DRIVE BELT PULLEY

FIGURE 3-10


MODEL 9501 ONLY

TRANSMISSION PULLEY



SECTION 8 TRANSMISSION

TRANSMISSION DRIVE BELT REPLACEMENT Secure the clutch pedal with rope as illustrated in Figure 3-11. Disconnect the spark plug lead and raise the unit vertically and rest on rear cover and engine.

SAFETY WARNING



Remove the rear blade belt (bottom drive pulley). See Rear Belt Replacement. Transmission belt may now be rolled off pulleys.

This belt is 44 inches in length.

TRANSMISSION BELT IDLER ADJUSTMENT With the clutch pedal depressed, adjust the belt keeper so there is 1/4" to 3/16" as shown in Figure 3-12.

.TRANSMISSION PULLEY REPAIR OR REPLACEMENT Remove transmission belt and retaining ring from transmission shaft. The pulley is keyed to the shaft. Carefully work pulley off shaft. Inspect key before reinstalling pulley and retaining ring.

INTERMEDIATE SPINDLE & PULLEY ASSEMBLY

MODEL 9500 ILLUSTRATED FIGURE 3-11

This assembly may not be dismantled. If damage has occurred to the shaft, pulleys or housing, the entire assembly must be replaced. To replace, remove the two housing screws.

MODELS 9500, 9501 ONLY REAR BLADE DRIVE BELT PULLEY IDLER 2. Loosen screw and slide blade brake to & BRAKE ASSEMBLY MODEL 9 5 0 0 ONLY end of slot. Tighten screw securely. To repair Or rep1ace; mower On end 3. Brake must ride in center of belt. Adjust

,secure to wall or other fixed object. Re- move the rear belt and idler spring. Dis- as required. connect blade engagement linkage rod and remove nut securing idler pulley arm. To remove idler pulley and o r brake assembly, remove idler pulley bolt from idler arm. When reinstalling, brake shoe must be aligned with pulley. Keep shoe free of dirt and oil. Refer to Blade Adjustment for brake adjustment. After installation of rear blade drive belt, pin on belt keeper (afixed to idler pulley arm) assembly must be positioned against edge of idler a rm and secured in place.

BLADE CLUTCH IDLER-ADJUSTMENT MODEL 9500 ONLY Remove idler spring. Adjust length of control rod and ball joint to enable end of control rod to slip freely into hole in bell arm on blade control assembly, when ball joint is installed on idler a rm and control rod is resting on frame. Shorten length of control rod and ball joint assembly one complete turn of ball joint. Assemble spring and secure cotter pin and nut. Re-check for proper adjustment.

REAR BLADE DRIVE BELT IDLER PULLEY BLADE CLUTCH IDLER ADJUSTMENT BELT RETAINER ADJUSTMENT MODEL 9501 ONLY MODEL 9501 ONLY To adjust:

retainer be flush to 1/32 inch Remove cotter pin and washer securing rod from belt when blade control lever is placed to control assembly. Loosen jam nut and in "OFF" position. To adjust loosen nut on remove rod from ball joint. Thread rod into

clearance is achieved. Tightennut securely. to ball joint with jam nut. rod pulley and move retainer proper ball joint nine (9) revolutions and secure rod

BLADE BRAKE ADJUSTMENT to control assembly, secure using washer MODEL 9 5 0 0 ONLY and cotter pin previously removed. Blade

clutch idler is now properly adjusted. The cutting blade must stop in not less than 3 or more than 6 seconds when the blade THROTTLE CONTROL ADJUSTMENT engagement arm is placed in "off" position. MODELS 9500, 9501 ONLY To adjust the blade brake: 1. Loosen cable retaining clip on engine.

1. Detach the blade engagement rod from 2. Place throttle lever in "Fast" position. the brake and idler pulley bell arm. This 3. Place speed control arm on in is done by unscrewing the 5/16" nut between the ball joint and bell arm.

fastest possible position without engaging choke.

2. Loosen the lock nut securing the ball joint to the brake rod. 4. Tighten cable retaining clip.

3. Screw the ball joint in a clockwise man- 5. Check to insure engine kill switch is en- ner to shorten the travel of the rod and gaged when throttle control lever is counterclockwise to lengthen the travel placed in "Stop" position. until the desired length is attained for 6. Check to insure choke on engine is in proper braking. f u l l choke position when throttle control

BLADE BRAKE ADJUSTMENT lever is not quite at full end of "choke" MODEL 9501 ONLY position. The cutting blade must stop in not less than ENGINE REMOVAL MODELS 9500, 9501 3 or more than 6 seconds when the blade ONLY engagement arm is placed in "off" position. Disconnect spark plug and throttle linkage.

Detach brake pull back spring and remove rear blade belt ,and transmission drive belt.

1. Place blade clutch control in "OFF" PO- Remove drive pulley and woodruff key and sition. remove the four engine mounting bolts.

To adjust the blade brake:


MODEL 9501 ONLY

TRANSMISSION DISASSEMBLY SEQUENCE

1. Bolt 2. Nut 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Cotter pin Brake spring Washer Brake band pin Brake band Key Retainer Brake drum Lower housing Needle bearing Thrust washer Bevel pinion Retaining ring

16. Key 17. Input shaft 18. Washer 19. Retaining ring 20. Retaining ring 21. Retaining ring 22. Sprocket 23. Flanged bearing 24. Output shaft 25. Drive shaft 26. Key 27. Key 28. Key 29. Key 30. Key 31. Spur gear 32. Spur gear 33. Sleeve bearing 34. Bevel gear

3 5. Clutch collar 36. Clutch collar 37. Spur gear 38. Gear 39. Shoulder screw 40. Screw 41. Cover plate detent 42. Detent. spring 43. Detent ball 44. Shifter fork 45. Upper housing 46. Bolt 47. Cam plate 48. Nylon slide 49. Shift lever 50. Shifter knob 51. Tap cover plate 52. Bracket 53. Washer

FIGURE 3-1 3

MODEL 9500 ONLY

TRANSMISSION DISASSEMBLY SEQUENCE

1. Lower housing 2. Retainer 3. Washer 4. Flanged bearing 5. Spur & bevel gear 6. Spur gear 7. Clutch collar 8. Clutch collar 9. Bevel gear 10. Sleeve bearing 11. Spur gear 12. Spur gear 13. Output shaft 14. Key 15. Drive shaft 16. Key 17. Key 18. 19. 20.

Retaining ring

I

.43

21. Sprocket 22. Retaining ring 23. Brake retainer 24. Input shaft 25. Key 26. Needle bearing 27. Thrust washer 28. Bevel pinion 29. Retaining ring 30. Shift fork 31. Ball bearing 32. Detent spring 33. Detent cover plate 34. Screw 35. Screw 36. Upper housing 37. .Bolt 38. Cam plate 39. Nylon slide 40. Shift lever 41. Shifter knob 42. Top cover plate 43. Bracket

12

14116

FIGURE 3-1 3A



TRANSMISSION DISASSEMBLY

GENERAL

For illustration purposes, we have shown the transmission removed completely from the mower. Any repairs, except replacing the lower transmission housing, can be made while the assembly is mounted on the mower.

SHIFT HANDLE REMOVAL

If the shift handle "snaps" from one shift position to another, this assembly is operating properly and it is not necessary to disassemble or remove it to ' make repairs internally on the transmission.

See Figures 3-13 and 3-13A for disassembly sequence. Note top and bottom of the cam plate location of springs (2) and ball bearings (2). These parts must be reassembled exactly o r the shift mechanism will not function properly. Also see Figure 3-14.

FIGURE 3-14

TRANSMISSION GEARBOX

Remove the transmission drive chain cover. Locate the connecting link in the drive chain and remove. See Figure 3-17. Re- move cotter pin securing brake shoe to brake drum.

See Figures 3-13 and 3-13A. Remove the seven screws securing the top housing and shift handle assembly to the lower housing. The top housing assembly can be lifted clear. The complete gear trains are now exposed for removal and inspection or replacement. Also see Figures 3-15 and 3-16.

FIGURE 3-15


MODELS 9500, 9501 ONLY 1. All parts should be washed clean with a

grease solvent such as Stoddards, o r kerosene. All excess solvent should then be blown off the parts so that they a re dry. Use Shell Co. "Darina AX" grease for relubrication of transmission.

2. Check external sprocket to insure that sprocket is not broken o r that key is not sheared.

3. Lift shaft assemblies out of lower housing. Inspect all parts for damage and replace damaged parts. Clutch collars must slide freely.

4. Check lower housing for damage and replace if necessary. The input shaft assembly should not be removed from the lower housing unless a part replacement is necessary. Check the input shaft needle bearings for. excessive wear. This

can be accomplished by rotating the input shaft and feeling the clearance. The clearance should be minimal for proper operation.

5. Relubricate lower housing by evenly distributing six (6) ounces of lubrication. Care should be taken to completely lubricate the pinion gear and thrust washer underneath the gear.

6. Replace shaft assemblies in lower housing taking care to install the locking tabs on the flange bearings in the cavities provided in the housing. Relubricate shaft assemblies by evenly distributing six (6) ounces of lubrication throughout the complete gear train.

7. Lubricate shifter cam plate with grease.

8. Replace upper housing onto lower housing and bolt securely into place.

SECTiON 9 WHEEL BRAKE

GENERAL This model mower is braked thru the transmission. The transmission driveshaft has a sprocket (drive chain) on one end and a brake drum on the other end. See Figure 3-17. A spring loaded brake shoe wraps around the drum and is actuated by the brake pedal.

BRAKE ADJUSTMENT MODEL 9500 ONLY Proper brake adjustment will allow the brake drum to turn freely while machine is moving. When the brake pedal is pushed, the brake shoe will tighten on the drum and stop the mower. See Figure 3-17. Adjust- ment is made by lengthening or shortening the rod from the brake pedal to the brake shoe. This is accomplished with the turnbuckle. Loosen the two jam nuts prior to adjustment. Re-secure them after proper brake adjustment is achieved.

BRAKE ADJUSTMENT MODEL 9501 ONLY Proper brake adjustment will allow the brake drum to turn freely while mower is moving. When the brake pedal is depressed the brake shoe will tighten on the drum and stop the mower. Adjustment is achieved


MODELS 9500, 9501 ONLY with the brake pedal pulled back against stop. Ad- tween brake drum and brake band lining as shown just brake band assembly using the brake band in Figure 3-17. Tighten jam nuts and mounting mounting screw and jam nuts on brake rod until screw securely. See Figure 3-17. there is approximately 1/64-1/32 inch clearance be-

~~~~~ ~ ~

SECTION 10

DIFFERENTIAL REMOVING DIFFERENTIAL .DRIVE SPROCKET Remove the spark plug lead. Stand mower on end, resting on engine. Secure mower so it will not tip during repairs. Locate and remove the master link on drive chain. See Figure 3-18. Remove chain, see Figure 3- 19. Remove the rear wheels and bearing assemblies (2). Slide the differential out of the chassis. The sprocket can now be removed or the differential disassembled for further repair or replacement.

parts should be thoroughly washed with a suitable solvent. The axle and gear assemblies must be replaced as a unit as the gears are permanently secured to their respective axles. Care should be taken not to damage the mating surfaces of the

When reinstalling master link, open casting halves as there is no gasket used to seal end must face toward front of unit the assembly. on chain slack side.

NOTE

DIFFERENTIAL REPAIR LUBRICATING DIFFERENTIAL Follow the instructions under REMOVING Prior to reassembly or lubrication all parts should DIFFERENTIAL DRIVE SPROCKET and be cleaned as stated under DIFFERENTIAL remove the drive sprocket. Remove all screws REPAIR. Pack the differential with a good grade securing the differential casting halves together. of packing lubricant i.e. Lawn-Boy “A” grease or. The differential parts can now be removed for in- automotive chassis grease. spection and replacement. See Figure 3-21. All


MODEL 9500 ONLY

CLUTCH SPRING

REAR WHEEL ANDBEVELGEAR

SHORT AXLE ANDBEVELGEAR

\ SPROCKET

14115

FIGURE 3-20

MODEL 9501 ONLY

CHAIN GUIDE

REAR WHEEL

CLUTCH SPRING

AND BEVEL GEAR

SPROCKET 14115

FIGURE 3-20A



FIGURE 3-21

DRIVE CHAIN TENSION

The chain tensioner is located under the chassis support bar. See Figure 3-22. Oc- casionally this may have to be tightened to maintain correct chain tension.

1. Remove spark plug lead. Stand mower on, end resting on engine. Secure mower so it will not tilt o r fall..

2. Loosen the nut on the chain tensioner.

3. Use a screwdriver to apply tension to the chain. Tighten to 3/32 inch maximum chain slack.

REAR WHEEL BEARING & AXLE LUBRICATION The rear wheel bearing should be lubricated every 25-30 hours of operation with Lawn-Boy Type A lubricant or a good automotive type chassis grease. See Figure 3-23.

FIGURE MODEL 9501

CHAPTER IV MODELS 9328, 9328E, 9328ES, 9368, 9368E, 9368ES ONLY

INTRODUCTION

Models 9328, 93283, 9328ES, 9368, 93683 and 9368ES compact riders are propelled by a geared transmission with three forward speeds and reverse. Maximum speed in first gear is: 2.6 MPH, second :gear 4.0 MPH, third gear 5.9 MPH and reverse gear 2.6 MPH.

An 8 H.P. recoil or electric start Briggs and Stratton four cycle engine with a maximum rpm range of from 3400 to 3600 rpm powers the mower. For engine service see an authorized Briggs and Stratton Dealer.

A unique feature is the gear-type;steering which gives the operator positive steering control, reduces ,feed-back of jolts and jerks. Geared steering with short coupled frame allows outstanding maneuverability for f a s t convenient mowing around 'obstructions.

The 32 or 36 inch floating pan may be ad- .justed to 5 different cutting positions between l-3/8 inches and 2-7/8 inches. The front wheels a re semi-pneumatic while the rear t ires are fully pneumatic and maintain 16-18 pounds air pressure.

A Service and Parking brake is included to provide sure, instant stops. The parking brake lock assures the owner of safestorage and starting.

Overall length is 54.5 inches. Width of 36 inch models is 41 inches. Width of 32 inch models is 35 inches.

MODELS 9328, 9328E, 9328ES, 9368, 9368E, 9368ES ONLY SECTION 2

SPECIFICATIONS

ENGINE

Idle rpm 1800 rpm's Operating rpm 3400 3600 rpm's maximum Oil requirement SAE 30 Wt. service MS Crankcase capacity 2-1/2 pints Spark plug Champion CJ8-Autolite A7N

TIRE SPECIFICATIONS

Front size 10.25 x 3.50 semi-pneumatic Rear size 13 x pneumatic 5.00-6

Pressure 16-18 PSI

SECTION 3 LUBRICATION

LAWN-BOY "A" GREASE, MULTIPLE- PURPOSE AUTOMOTIVE CHASSIS GREASE, MOB11 OIL COMPANY NO. 130204 OR EQUIVALENT: 1. Lubricate rear axle bearings at grease

fittings.

2. Lubricate blade shaft housings at grease fittings.

3. Lubricate blade pulley spindle assembly of 32" rider at grease fitting.

4. Front axles at wheel and at axle mounting bushings.

5. Steering gears.

SAE #30 OIL

1. All pivot points other than specified above.

SHELL EXPRO 71030 GREASE OR EQUIVALENT:

1. Transmission: 10.5 oz. evenly distributed. Grease thrust area of each gear and shaft bearing surfaces of casting.

2. Differential: 1.5 oz. Grease thrust area of each gear and shaft bearing surfaces of casting.


MODELS 9328, 9328E, 9328ES, 9368, 9368E, 9368ES ONLY

SECTION 4 HARDWARE TORQUES

Torque to values given for thread size unless listed separately.

THREAD SIZE 10 16 1/4 20 5/16 18 3/8 16

DESCRIPTION 608002 Screw Blade to Adaptor

608013 Screw Adaptor to Shaft

603773 Nut Transmission Idler Pulley

603781 Nut Pan Idler Pulley

607995 Screw Pulley to Engine (8 HP)

TORQUE INCH POUNDS 25 to 30 inch lbs. 63 to 75 inch lbs. 142 to 170 inch lbs. 190 to 225 inch lbs.

TORQUE INCH POUNDS 190-250 inch pounds

190-250 inch pounds

149-195inch pounds

149-195 inch pounds

268-350 inch pounds

150-180 inch pounds


SECTION 5

PROBLEM

Hard steering

Blade won't 'turn

TROUBLESHOOTING

STEERING

CAUSE

Lack of lubricant

Gears and/or bushings worn

Tie rods bent

Steering shaft o r a rm broken

REMEDY

Lubrication Section 3

Steering disassembly and inspection Section 6

Straighten or replace Section 6

Disassembly and replacement Section 6

.BLADE HOUSING AND BLADE

Belt off pulleys

I damaged Blade nut loose Seized bearings

Blade leaves swirl marks in lawn

Housing unlevel

Blade unlevel or bent

Replace Section 7

Replace Section 7

Tighten Section 7 Refer to Spec. Sheet Torque

Correct housing level Section 7

Replace blade Section 7

SERVICE BULLETIN REFERENCES a a a a a e 1 1 8 3 REVISED 1977


BLADE HOUSING AND BLADE (CONT)

PROBLEM

Blade belt comes off (Rear)

Blade belt comes off (Front)

Mower will not propel

CAUSE

Belt keeper loose

Broken belt

Belt pulleys loose

Broken belt

Pulleys damaged o r loose

Idler pulley broken o r bent

Idler spring disconnected o r distorted

DRIVE PROBLEMS

Chain loose

Chain broken

Differential broken

Sprocket worn or broken

Drive belt broken or damaged

Transmission won't shift

REMEDY

Adjust and tighten

Replace

Tighten

Replace

Tighten o r replace

Tighten

Replace

Adjust

Repair or replace

Repair or replace Section 9

Replace Section 8

Replace Section 8

Repair Section 8



Engine slows down and stops

PLUG CONDITION

Black carbon or sooty deposit

Pitted or burned electrodes, white, light tan or blistered deposits. Rapid wear of electrode

Cracked or broken Plug

Cracked o r broken insulator on lower end of plug

Widening of gap


FUEL TROUBLE

CAUSE

a. Fuel tank empty

b. Water in fuel

c. Old fuel in tank gums up tank, fuel line and carburetor

d. Shut-off valve closed

a. Vent hole in fuel tank cap plugged

b. Fuel line or strainer clogged

c. Fuel tank runs dry

REMEDY

a. Fill tank

b. Drain fuel from tank and carburetor and replace with fresh fuel

all parts involved c. Empty out old fuel and clean

d. Open valve

SPARK PLUG TROUBLE

a. Unplug hole

b. Clean out fuel line or strainer

c. Refill tank

CAUSE RECOMMENDATION

a. Breaker points dirty or out of adjustment

b. Weak condenser

c. Incorrect plug



c. Install correct plug

a. Incorrect plug a. Install correct plug

a. Careless installation a. Replace plug of plug

a. Center electrode a. Replace plug strained when regapping Plug

a. Normal wear a. Clean and regap

17-85 REVISED 1977


FIGURE 4-1


MODELS 9328E, 9328ES, 9368, 9368E, 9368ES ONLY 9328, SECTION 6 FRONT END

STEERING The steering is a positive gear type system. The steering shaft pinion gear engages the idler shaft gear which drives the steering EACH gear. The steering gear is attached to the lower steering shaft. Two tie rods connect front axle assemblies allowing the wheels to A

turn in the desired direction.

STEERING DISASSEMBLY 1. Remove 2 screws securing.steering col-

umn to upper steering shaft and remove steering column.

2. Remove lower 3 screws, as shown, on each side of steering column channel and remove channel.

3. Remove cotter pin and bushing from steering column.

4. Remove four screws securing steering support bracket to frame and remove

5. bracket Using a punch, remove roll pin securing pinion gear to steering shaft and remove gear.

NOTE When re-installing pinion gear in- S H A F T GEAR stall with bevel side up.

6. Remove roll pin securing steering gear to lower steering shaft and remove steering gear and steering idler shaft gear assembly.

NOTE When reinstalling steering idler gear install gear assembly as shown to allow full turning radius.

etc. Replace as required. During reassembly apply a light coat of Lawn-Boy “A” grease or equivalent. S H A F T

7. Inspect all gears, shafts, roll pins for wear

COMPONENTS LOWER STEERING

NOTE Front wheels must be facing in straight ahead position. Install up- STEERING per steering shaft in steering sup- PINION port bracket with the steering column GEAR holes perpendicular to mower.

STEERING IDLER STEERING GEAR

8. Reinstall steering components in reverse SHAFT GEAR order of disassembly. A S S E M B L Y S T E E R I N G

FIGURE 4-5 34009



<

BELT GUARD

MOWER DRIVE BELT

!BLADE DRIVE BELT

HEIGHT ADJUSTMENT ASSEMBLY :BLADE PULLEY ASSEMBLY

BLADE HOUSING

BLADE ADAPTER

*32 INCH PAN HAS TWO 36 INCH PAN HAS THREE

.,

2406 I FIGURE 4-6


BLADE DRIVE & BLADE HOUSING ASSY. The cutting blade is driven by a system of V belts and pulleys.

4. Place cutting height adjustment control BLADE TOP VIEW BLADE

in highest position. Remove two pivot bolts "A" from triangular bracket as il- SECONDARY

lustrated. (One on each side- of unit.) CAUTION: Exercise care when removing PRIMARY

second bolt, pan will drop to floor. Re- DRIVE BELT

move two pivot bolts "B" as illustrated and slide blade housing from -mower.

PULLEY INTERMEDIATE

NSMISSION CLUTCH IDLER

ENGINE SHEAVE TRANSMISSION

DRIVE BELT 34080

FINAL BLADE DRIVE BELT REPLACEMENT

1. Follow steps 1 thru 5 under PRIMARY BLADE DRIVE BELT REPLACEMENT.

2. Remove 8 screws securing belt cover and remove belt cover.

FIGURE 4-11

TRANSMISSION DRIVE BELT REPLACEMENT

1. Follow steps 1 and 2 under PRIMARY BLADE DRIVE BELT REPLACEMENT.

2. Depress clutch pedal to take tension off transmission drive belt and remove belt from transmission pulley.

3. Remove belt keeper.

4. Remove belt.

5. Install new belt by reversing procedure.


REVISED 1977

3. Using a piece of rope remove idler spring as shown and remove worn belt.

4. Replace belt, attach idler spring and reassembly mower pan to mower frame.

11-90

CUTTING HEIGHT ADJUSTMENT Mower pan may be set at five different cutting heights - from 1.38 inches to 2.88 inches. It is adjusted automatically to these five positions by pulling up the release latch on height adjustment lever, and shifting the lever to desired position. Latch is then re- ? leased locking pan in that position.



LUBRICATION OF BLADE SHAFT HOUSING ASSEMBLY

32 INCH MODELS

1. Use a grease gun and apply grease to three (3) zerk fittings located on spindle housing. Apply grease until grease appears at bearing housing. Refer to lubrication section.

36 INCH MODELS

1. Use a grease gun and apply grease to three (3) zerk fittings located on spindle housings. Apply grease until grease appears at bearing housing. Refer to lubrication section.

BLADE' SERVICING

1. Remove three mounting screws from blade housing assembly and remove blade. Re-torque blade to correct torque.

2. If blade is sharpened it should be balanced.

3. Replace blade if bent o r distorted o r if badly worn.

36" MODELS 34018

FIGURE 4-16



SWITCH

GEAR HOUSING COVER

BRACKET

GASKET

DRIVING DOG

I GEAR-30 TOOTH

GEAR-30 TOOTH SPROCKET

\

BEVEL GEAR

FIGURE 4-18 65042

MODELS 9328E, 9328ES, 9368, 9368E, 9368ES ONLY 9328, SECTION 8

TRANSMISSION I ‘ TRANSMISSION REPAIR OR

REPLACEMENT SAFETY WARNING

ALWAYS MAKE SURE IGNITION KEY IS IN “OFF” POSITION AND

NECTED BEFORE INSPECTING AND REPAIRING THE MOWER.

SPARK PLUG LEAD DISCON-

1. Remove seat from seat spring. Remove battery from electric start models. Re- move throttle control cable from engine.

2. Remove drive chain. (Refer to CHAIN REPLACEMENT.)

3. Remove brake drum from transmission drive shaft by removing retaining ring from end of shaft.

4. Remove nine (9) screws securing transmission cover plate, and remote cover plate to expose gear train.

5. Remove gear and axle assemblies and repair or replace gears as required. TRANSMISSION LUBRICATION

Refer to LUBRICATION. MOWER BRAKE The mower is stopped by applying foot pressure to both clutch pedal and brake foot pedal, which activates a transmission brake shoe. Stopping action occurs through the transmission, not the mower wheels. This brake is self-adjusting no adjustment necessary. If no brake action is apparent, check linkage, springs and brake shoe for wear. Repair o r replace as required.

PARKING BRAKE The mower is equipped with a foot-operated parking brake. A separate brake lever on the center console engages the parking brake after the brake pedal is depressed. To release, depress foot brake.

CLUTCH Mower drive clutch is pre-set at the factory, and is self-adjusting; therefore, no adjustment is required. If no clutch action is apparent, check linkage and springs. Repair or replace as required. SERVICE BULLETIN REFERENCES 11-93

REVISED 1977


I ENGINE SHEAVE

ASSEMBLY PULLEY IDLER

24068

FIGURE 4-22 24068



DIFFERENTIAL REPAIR O R REPLACEMENT

1. Raise rear of mower up approximately

2. Remove rear wheels. 3. Remove chain guard. Remove master

link from drive chain and remove chain. 4. Remove 4 screws securing rear axle

bracket assembly to main frame. 5. Remove rear axle and differential as-

sembly. 6. Repair or replace axle and/or differential

assembly as needed.

24 inches.

NOTE

When installing axle and differential assembly to mower frame, the axle must be perpendicular to mower frame. Drive chain must be tight to 3/32 inch maximum slack. To adjust loosen axle bracket assembly mounting bolts and move axle in desired direction. Tighten axle bracket assembly screws securely.

DIFFERENTIAL LUBRICATION Refer to CHAPTER I1 SECTION 3.

DRIVE CHAIN ADJUSTMENT 1. Loosen two bolts on each side of both

rear axle bracket assembly. This will allow slight movement of the axle within the slots of the main frame.

2. Pull axle to rear of unit to create additional tension; pull axle to front of unit to relax tension. CARE must be taken to align differential and axle perpendicular to machine axis.

3. Correction tension should allow 3/32 inch maximum slack with light thumb pressure.

4. Tighten rear axle bracket assembly screws securely.

DRIVE CHAIN REPLACEMENT 1. Remove chain guard, connecting link from

chain and remove drive chain. Repair o r replace. IMPORTANT: Open end of master length clip must face toward front of unit on chain slack side. Refer to CHAIN ADJUSTMENT for proper tension.

FIGURE 4-24 CONNECTING

LINK

FIGURE 4-24 CONNECTING

LINK

FIGURE 4-25 LOCK

SAFETY WARNING ALWAYS MAKE SURE IGNITION KEY IS IN “OFF” POSITION AND

NECTED BEFORE INSPECTING AND REPAIRING THE MOWER.

THROTTLE CONTROL ADJUSTMENT 1. Loosen throttle cable retaining clip on

engine. 2. Place throttle control lever in f a s t posi-

tion, and place speed control arm on engine in fast position, without engaging choke.

4. Check to insure engine kill-switch is engaged when throttle control lever is placed in stop position manual s tar t models only.

5. Check to insure choke on engine is in full choke position, when throttle control lever is not quite at full end of choke position.

SPARK PLUG LEAD DISCON-


MODELS 9328E, 9328ES, 9368E, 9368ES ONLY SECTION 10

WIRING DIAGRAM

CABLE STARTER

ENGINE

BATTERY

CABLE GROUND

CABLE POSITIVE

WIRE ENGINE CHARGING

SECTION 1 0 WIRING DIAGRAM

MODELS 9266, 93298 ONLY WIRE-BLADE

WIRE BLADE SWITCH

I - TRANSMISSION

WIRE-MAGNETO

ENGINE

MODELS 9329ES, 9369ES ONLY WIRE-BLADE WIRE BLADE SWITCH

SWITCH GROUND WIRE

SWITCH TRANSMISSION

W MODULE

WIRE-MAGNETO GROUND WIRE-MAGNETO

WIRE-ENGINE CHARGING

CABLEPOSITIVE

I CABLE-GROUND

BATTERY

ENGINE

CABLE-STARTER


CHAPTER V STORAGE PROCEDURE

ALL MODELS

Grease or lubricate where necessary. See Preventative Maintenance.

Drain gas tank and carburetor bowl. Check oil level in crankcase. Remove spark plug. Squirt a small amount of oil in cylinder and work engine manually to coat, cylinder walls.

Electric Start Model: Remove battery, check fluid level, and charge the battery to its capacity, Charge battery fully once per month while in storage.


.SECTION 12 ='SNOW BLOWERS

MODELS 2680,2680A, 26808 AND 2650,2650A, 26508

PART A

TABLE OF CONTENTS PART A MODELS 2680,2680A, 2680B, 2650,2650A AND 2650B

PART B MODEL 1840 AND 1840A PART C Model 1850

PART A CHAPTER I ADJUSTMENTS .12-2 CHAPTER I1 BELT REPLACEMENT .12-4 CHAPTER III WHEEL DRIVE GEARCASE

CHAPTER IV TRACTION DRIVE

CHAPTER V DRIVE DISC PULLEY

CHAPTER VI AUGER GEARCASE

CHAPTER VI1 LUBRICATION AND

SERVICING .12-5

SERVICING .12-6

IMPELLER PULLEY SERVICING 12-7

SERVICING .12-9

MAINTENANCE. 12-11

PART B CHAPTER I TROUBLESHOOTING 12-13 CHAPTER I1 ADJUSTMENTS. .12-13

CHAPTER I11 LUBRICATION AND MAINTENANCE. 12-14

CHAPTER IV BELT REPLACEMENT .12-14 CHAPTER V WHEEL DRIVE

CHAPTER VI AUGER PULLEY AND

CHAPTER VI1 DRIVE PULLEY

GEAR CASE 12-15

AUGER GEARCASE 12-15

REPLACEMENT. 12-15

PART C

CHAPTER I1 LUBRICATION AND CHAPTER I ADJUSTMENTS 12-16

MAINTENANCE. .12-17 CHAPTER I11 BELT REPLACEMENT -12-17 CHAPTER IV CONTROL MECHANISMS .12-18 CHAPTER V AUGER SERVICING 12-19 CHAPTER VI ENGINE REMOVAL AND

REPLACEMENT. .12-20

MODELS 2680, 26804A,2680B Powered by a 4 cycle 8 H P gasoline engine. For ,engine servicing or repair, contact your local Briggs and Stratton dealer or the Briggs and Stratton Corp., Milwaukee, Wis- consin.

MODELS 2650, 2650A, 2650B Powered by a 4 cycle 5 H P gasoline engine. For engine servicing or repair, contact your local Briggs and Stratton dealer or the Briggs and Stratton Corp., Milwaukee, Wis- consin.


CHAPTER I

S A F E T Y WARNING

DISCONNECT SPARK PLUG WIRE BEFORE SERVICING OR MAKING ADJUSTMENTS.

TRACTION CLUTCH ROD ADJUSTMENT

1. Move shifter lever into the neutral position and push snow blower, it should move.

2. Move shifter lever into any of the forward speeds and push snow blower, it should not move.

3. If unit does not move when shifter lever is in neutral, adjust according to the following instructions.

a. Remove clevis pin from clevis on clutch rod. (Fig. 1).

b. Turn clevis to lengthen rod if unit won't move with lever in the forward (N) position. (Fig. 2.) Turnclevis to shorten rod if unit won't move when the lever is pulled back against the

FIGURE 2

back of shifter panel.. Pull directly in back of the (N) position and in back of the (3) position. (Fig. 2.)

c. With clutch rod reconnected move snow blower again. Repeat adjustment until you can move snow blower with shifter lever in neutral.

SHIFTER ROD ADJUSTMENT

1. Place shifter lever in the neutral position.

2. Push shifter rod end (Fig. 1) into the unit as far as it will go.

3. Move Shifter lever into the reverse position.

4. Connect the shifter rod to the shifter rod end using the 1/4" carriage bolts, lock- washers, and hex nuts; making certain the head of the bolts a r e on the slotted sides of the rods. (Fig. 3.) Slide the two rods apart in opposite directions as fa r as they will go. Be certaintheedges of the two rods are parallel and tighten securely.


CARRIAGE BOLT

CARRIAGE BOLT

FIGURE 3

SCRAPER. BLADE ADJUSTMENT The scraper blade is adjustable to obtain a level scraping action for clean and smooth snow removal and to compensate for scraper blade wear. To adjust the scraper blade loosen the nuts securing the blade to the auger housing. Move the blade up o r down to level position and tighten nuts securely.

SKID ADJUSTMENT The skids (Fig. 4), mounted on each side of the auger housing, adjust the distance the

scraper blade is raised above the ground surface. When removing snow from a gravel o r uneven-surface, it is advisable to keep the scraper blade as high above the surface as possible to prevent possible damage to the auger. On a blacktop o r concrete surface, keep the scraper blade as close to the surface a s possible. To adjust skids, raise Snow Thrower a few inches off the ground and loosen the nuts securing the skids to the auger housing. Move skids up or down to desired position and tighten nuts securely. Adjust both skids to the same height to keep the auger level.

BELT ADJUSTMENT Traction Drive and Impeller Drive. No adjustment required. These belts have a spring loaded idler which makes them self- adjusting. Periodically, check idler to be sure ' it is operating freely and providing tension.

If belts come off pulleys--check for loose o r misaligned pulleys; distorted o r misaligned idler pulleys. The idlers should hit squarely on the belts. Also, the belt fingers must be 1/16" 1/8" from belt. Refer to Chap. 11, Fig. 5 & 6.


CHAPTER II BELT REPLACEMENT

The belts on the LAWN-BOY Snow Blower c. Remove impeller drive belt from are specifically designed and engineered to engine pulley. provide long service. If belt replacement is required, order by part number to insure you have the right belt. Do not use substi- d. Remove traction belt from engine tute belts. pulley.

NOTE e. Loosen capscrew on belt finger. (Fig. 6.)

Belt fingers (Fig. 5 & Fig. 6) must be adjusted 1/16'' 1/8" from belt.

BELT REPLACEMENT

1. Traction Drive Belt

a. Remove belt guard.

b. Remove springs from impeller clutch idler and traction idler. (Fig. 5. )

f. Tip ,Snow Blower forward and rest unit 'on drift cutter.

"g. Remove bottom cover.

h. Remove belt from traction pulley. (Fig. 7.)

i. Remove by slipping between traction pulley and disc.

j. Replace by reversing procedure.


2. Impeller Drive Belt

a. Follow steps A through I of traction belt removal.

b. Remove impeller belt by slipping between traction pulley and disc.

c. Replace by reversing procedure.

CHAPTER 111 WHEEL DRIVE GEARCASE SERVICING

SAFETY WARNING

1. DISCONNECT SPARK PLUG WIRE BEFORE SERVICING OR MAKING ADJUSTMENTS.

2. Drain fuel from tank and tip Snow Blower forward and rest on drift cutting bar.

3. Remove wheels. Count spacers for proper replacement.

4. Remove bottom cover plate and transmission cover plate. Fig. 10.

NOTE

To facilitate removal of transmission plate, grasp the end (gear end) of the axle and pull the axle and cover plate away from unit to dislodge end of plate. Fig. 9.

5. Remove axle roll pin (Fig. 8).


6. Remove gears, gear and axle and interior Locate and count spacers and wash- gearcase housing plate. Fig. 10. ers for proper replacement.

! i

I

GEAR ASSEMBLY \

SIDE ASSEMBLY PLATE.

TRANSMISSION COVER PLATE

BOTTOM COVER

F I G U R E 10

CHAPTER IV TRACTION DRIVE SERVICING

1. Traction Drive Assembly Removal

To remove the traction drive assembly follow steps 1 thru 6 Chapter I11 Gear Case Disassembly; then:

a. Remove shift control linkage keys (2) and transmission arm (bell crank assembly) nut Fig. 11.

NOTE

Note position of spacers and washers, before removal for proper replacement.

c. Remove complete drive assembly Fig. 13.


DRIVE BEARING SHAFT

DRIVE \

BEARING

CLUTCH

SHIFT ROD

LINK

SUPPORT ARM ASSEMBLY

I TRANSMISSION ARM

(BELL CRANK) FIGURE 12

2. Drive Roller Replacement

a. Follow all steps in Traction Drive Assembly Removal.

b. Drive (use plastic or leather hammer) open end of drive (hex) shaft out of bearings Fig. 13.

NOTE

End of driveshaft may have to be ground down slightly with file o r emery cloth to facilitate removal. When the shaft is driven through the bearing, the bearing at the opposite end (gear end) will dislodge from its retainer.

c. Remove drive roller from roller hub- Fig. 12.

CHAPTER V DRIVE DISC PULLEY lMPELLER PULLEY SERVICING

To repair or replace these items the trac- 2. IMPELLER PULLEY REMOVAL tion drive assembly must be removed refer to Chapters I11 and IV. The Impeller pulley may be removed

after the drive disc pulley by:

1. DRIVE DISC PULLEY REMOVAL a. Loosen the two (2) set screws and pull pulley out on shaft until it stops

Remove the two (2) belt idler springs, at frame housing. the two (2) belts and the retainer ring on the end of the driven shaft. This will b. Loosen collar under impeller disc by allow removal of the drive disc pulley. loosening set screw See Fig. 15.

IMPELLER PULLEY

FIGURE 14

NOTE c. Place unit in "normal" upright posi-

tion and remove auger bearing grease fittings and auger bearings. Refer to Chap. VI, Fig. 19.

Remove and count Spacers forproper alignment.

d. Pull auger, gearcase, impeller and shaft from main frame housing to free impeller drive pulley and collar. See Fig. 16.

e. Augers may be replaced simply by removing the shear pins.

FIGURE 15 FIGI' i


CHAPTER VI

1.

2.

3.

4.

5.

AUGER GEARCASE SERVICING

Drain gearcase.

Remove gearcase plug Fig. 17.

Remove side cover plate (3 screws) and spacer Fig. 18.

Push gearcase housing towards impeller end of shaft. This will expose the bearing and bearing race at the front end of the shaft.

Remove bearing, bearing race, retainer ring and spacer Fig. 18.

6. Slide auger shaft out of open end of gearcase exposing the bronze bearing Fig. 18.

7. The main drive shaft may now be pushed forward through the gearcase head exposing the worn gear, spacer and rear bearing Fig. 18.

NOTE

When reassembling auger gearcase, the adjustment plug (Fig. 17) should be tightened until snug and back off until cotter key can be installed.

Gearcase must be filled to bottom of level fill plug (Fig. 17) with S.A.E. 30 weight oil. Remove level fill plug to fill.


AUGER BEARING

GREASE .AUGER FITTING SHAFT

GEARCASE I

WORM WHEEL RETAINING

BEARING

I GASKET SHEAR PIN WASHER

COVER AUGER

FIGURE 19

CHAPTER VI1 LUBRICATION AND MAINTENANCE

SAFETY WARNING


DAlLY CHECK OIL

1. Remove dirt from around oil fill before removing. Check engine oil with Snow Blower on level ground and engine stopped. Add oil when needed.

2. Make general visual inspection of Snow Blower for loose o r damaged parts. Check nuts and bolts periodically to insure against looseness caused by vibration o r rough handling Damaged parts should be repaired or replaced.

EVERY 10 OPERATING HOURS 1. Grease Automotive Wheel Bearing

Type.

Clean off grease fittings before attaching gun.

a. Drive Gears--One fitting on left side behind wheel Fig. 20. Apply a generous amount with pressure type gun.

b, Auger bearing support--two fittings, one on each end of auger shaft. (Fig. 21.) Grease until grease comes out of bearings. Wipe off excess grease. Grease with pressure type gun.

c. Snow Chute Apply grease to control sprocket and chute teeth.

2. Oil--SAE 30

a. Oil all lever pivot points and linkages.

b, Idlers.

ci Axle Bearings. (Hole in top of bearing.)

3. Gear case--Although the gear case is filled at the factory, be sure to check level before first use each season and periodically during the season. Keep it full to bottom of level plug hole with SAE 30 oil. Remove vent plug to fill. (Fig. 21.)


12-12

SECTION 12 SNOW BLOWERS -PART B

MODELS 1840,1840A

TABLE OF CONTENTS PART B MODELS 1840,1840A SEE PART A FOR MODELS 2680, 2680A, 2650, 2650A, 2650B

CHAPTER I TROUBLE SHOOTING 12-13

TRACTION CLUTCH ROD ADJUSTMENT 12-13 SKID ADJUSTMENT 12-13 BELT ADJUSTMENT 12-13

CHAPTER I11 LUBRICATION AND MAINTENANCE 12-14

A U G E R D R I V E B E L T . . 12-14 TRACTION DRIVE BELT 12-14

CHAPTER I1 ADJUSTMENTS

CHAPTER IV BELT REPLACEMENT

CHAPTER V WHEEL DRIVE GEAR CASE SERVICE

CHAPTER VI AUGER PULLEY AND AUGER GEAR AND FRICTION DISK REPLACEMENT 12-15

CASESERVICING 12-15 CHAPTER VI1 DRIVE PULLEY REPLACEMENT 12-15

SAFETY WARNING,



CHAPTER I TROUBLE SHOOTING 1. Worn or broken belts

A. Check pulley alignment B. Belt fingers not set within 1/16 1/8 of belt

when the drive belt is engaged C. Idlers loose or frozen up due to lack of

lubrication D. Substitute belts used E. Loose pulleys F. Loose or broken idler spring G. Belt cover removed from unit H. Auger or impeller jammed

2. Augers won’t turn A. Auger shear pins broken

Note: Do not use substitute shear pins. These are special pins that will break when items other than snow are jammed into the augers. Substitute pins may be too hard and damage may result to the augers or auger gear case

B. Worn or broken belt C. Internal damage to auger gear case D. Sheared roll pin-auger pulley

A. Worn or broken belt B. Check traction lever adjustment C. Check friction disk D. Check wheel drive gear case E. Wheel pins broken or missing F. Idler spring off or broken

3. Unit doesn’t move

CHAPTER II ADJUSTMENTS CLUTCH ROD Place shift lever in the neutral (N) position. Attach lower end of control rod into center hole of shift arm and secure with spring clip (Fig. 1). Try pushing Snow Thrower forward and backward. Wheels should turn. Pull shift lever back into the reverse (R) position and put shift lever into the forward (F) position to see if these positions are approximately the same distance from the neutral (N) position. If they are, no further adjustment should be required. If reverse is further away from neutral than for-

Fig. 1

ward, move lower end of control rod down one hole in shift arm. If forward is further away from neutral than reverse, move lower end of control rod up one hole in shift arm Place shift lever in the neutral (N) position and start engine. Keep hands and feet away from auger and chute, and be certain the auger clutch is in the “off” position. Try forward and reverse positions to make sure the traction shift lever is properly adjusted when your Snow Thrower is running; if not, adjust again according to the instructions above. With shift lever in forward position unit should move ahead; with shift lever in reverse position unit should back up; and with shift lever in neutral position unit should show no signs of moving in either direction. Stop engine before removing lower end of control rod from shift arm or when making any other adjustment.

SKID ADJUSTMENT The skids (Fig. 2), mounted on each side of the auger housing, adjust the distance the scraper blade is raised above the ground surface. When removing snow from a gravel or uneven surface, it is advisable to keep the scraper blade as high above the surface as possible to prevent possible damage to the auger. On a, blacktop or concrete surface, keep the scraper blade as close to the surface as possible. To adjust skids, raise Snow Thrower a few inches off the ground and loosen the nuts securing the skids to the auger housing. Move skids up or down to desired position and tighten nuts securely. Adjust both skids to the same height to keep the auger level.

BELT ADJUSTMENT Traction Drive and Impeller Drive. No adjustment required. These belts have a spring loaded idler which makes them self-adjusting. Periodically check idler to be sure it is operating freely and providing tension. If belts come off from pulleys make sure that the- pulleys are not loose and that the idler is not distorted. Idler should hit squarely on the belts. With drive engaged, belt fingers should be within 1/16” to 1/8” of belts.


CHAPTER 111 LUBRICATION AND MAINTENANCE

DAILY 1.

2.

10

1.

Check oil. Remove dirt from around oil fill before removing. Check engine oil with Snow Thrower on level ground and engine stopped. Add oil when needed. Make general visual inspection of Snow Throw- er for loose or damaged p a r t s . Check nuts and bolts periodically to insure against looseness caused by vibration or rough handling. Dam- aged parts should be repaired or replaced:

OPERATING HOURS

Grease Automotive wheel bearing type. NOTE: Clean off grease fittings before attaching gun.

A. Auger Bearing Support Two fittings, one on each end of auger shaft (Fig. 3). Grease until the grease comes out of bearings. Wipe off excess grease. Grease with pressure type gun.

B. Snow Chute Coat underside of ring. (It is not necessary to remove chute.)

C. Idlers Fill groove and coat outside of shaft with grease. Remove idlers by taking snap ring and washer off idler arms and sliding the idler off the shaft.

2. Oil-SAE 30 A. Oil all lever pivot points and linkages. B. Axle bearings (hole in top of bearing).

NOTE: Auger gear case and traction drive gear case each contain 1/2 pint of wheel bearing grease. It is not necessary to refill unless in teardown.

CHAPTER IV BELT REPLACEMENT

BELT REPLACEMENT The belts on this Snow Thrower are specifically designed and engineered to provide long service. If ?- belt replacement is required, order by part number to insure you have the right belt that will provide the life and service required. Do not use substitute belts.

AUGER DRIVE BELT 1. Remove belt guard (Fig. 2). 2. Remove belt guide (Fig. 4). 3. Remove impeller idler spring (Fig. 4). 4. Remove' auger belt from engine pulley (Fig. 4). 5. Push belt down (off from bottom groove in

auger pulley) so that it rests on the auger housing.

6. Remove auger bearing from both ends of auger shaft (Fig. 3).

7. Pull out entire auger and impeller assembly (Fig. 3).

8. Remove old belt and replace with new one. 9. Reverse the above procedure to reassemble.

TRACTION DRIVE BELT 1. Follow steps 1 through 7 of auger drive belt re-

2. Remove traction drive idler spring (Fig. 4). 3. Remove old belt and replace with new one (Fig.

4. Reverse procedure to reassemble Snow Thrower. NOTE: Be sure to have the new belt resting in bottom auger housing before sliding auger and impeller assembly back in,

placement.

4).

Fig. 3 Fig. 4 12-14 SERVICE BULLETIN REFERENCES

CHAPTER V WHEEL DRIVE GEAR CASE SERVICING AND FRICTION DISK REPLACEMENT

1. Disconnect spark plug lead. 2. Drain fuel from tank and tip Snow Thrower forward and rest handle on bench. 3. Remove wheels. 4. Remove bottom cover plate. 5. Remove bolts holding both side plates to unit. 6. Pull left-hand side plate l o o s e so traction arm spring

7. Complete unit can now be removed for servicing. 8. Gear and Friction Disk Replacement:

A. Remove hex. lock nuts on left-hand side of

NOTE Locate and count spacers and washers for proper replacement.

friction disk can be replaced.

can be released.

gear case cover.

9. Gear case can now be opened up for servicing and

REF. LET. ARE THE SAME IN OWNER'S MANUAL AS IN SERVICE MANUAL.

CHAPTER VI AUGER PULLEY AND AUGER GEAR CASE SERVICING

1. Follow steps 1 through 6 of Chapter IV for removal

2. Remove augers from shaft. 3. Gear case can now be opened for servicing. 4. Be certain augers are replaced properly.

of auger gear case assembly.

REF. LET. ARE THE SAME IN OWNER'S MANUAL AS I N SERVICE MANUAL.

CHAPTER VI1 DRIVE PULLEY SERVICING

1. Follow steps 1 through 3 of Auger Belt Replacement, Chapter IV. 2. Follow step 2 of Traction Belt Replacement, Chapter IV. 3. Loosen or remove engine. 4. Follow steps 1 through 7 of Chapter V for removal of

5. Remove bolts holding back plate assembly to main frame. 6. Remove bolts holding bearing support to main frame.

wheel drive gear case and axle.

NOTE Locate and count spacers and washers for proper replacement.

7. Complete drive pulley assembly can now be removed for servicing.

EM REF. LET. ARE THE SAME I N OWNER'S MANUAL AS I N SERVICE MANUAL. SERVICE BULLETIN REFERENCES 12-15

i

SECTION 12 SNOW THROWERS PART C

MODEL 1850

CHAPTER I ADJUSTMENTS CLUTCH CONTROL The clutch control cable must be properly adjusted to obtain maximum performance. Too little tension will allow the belt to slip resulting in premature wear. Too much tension will render the brake tab inoperative. Attach the clutch spring to the clutch cable assembly (See Figure 1) such that most of the slack is removed from the cable in the neutral position. Leave only enough slack to allow the brake tab (See Figure 2) to contact the drive belt firmly. (It may be necessary to tighten the clutch after several hours running time to compensate for belt stretching and wear.)

Be certain to adjust the idler pulley and brake tab so that they are in alignment with the center of the belt travel. This is done by removing the idler arm and bending the ends to obtain the proper angle.

DISCHARGE CHUTE AND DEFLECTOR

In order to maintain proper detent pressure it may be necessary to adjust the pivot assembly (See Figure 3). Increased pressure is obtained by adding additional 7/16” washers to the deflector control shaft. A more positive adjustment may be made by removing the deflector pivot assembly and bending the detent arm toward the deflector shaft.

Note: Excessive pressure may make the deflector handle difficult to operate.

FIGURE 1

SHAFT

FIGURE 2

DEFLECTOR CONTROL

SHAFT PIVOT

SNOW DEFLECTOR

FIGURE 3


\

CHAPTER II LUBRICATION AND MAINTENANCE

If the felt plug is dislodged, it must be replaced by removing the right side plate and support shaft assembly. (See Figure 4) the plug should be flush with the inner end of the stub shaft bearing.

AUGER SUPPORT BEARING IDLER PULLEY SHAFT

The auger, support bearing should be lubricated every 10 hours. Use SAE #30 oil to lubricate the felt plug in the center of this bearing Add oil until it appears at the hole (See Figure 3).

FIGURE 3

Note: Do not force the spout of the oil can into the oil hole! This will push the felt plug out of the bearing and into the center cavity of the impeller shaft, resulting in a lack of lubrication at the bearing surface.

SERVICE BULLETIN REFERENCES REVISED

The idler pulley shaft should be lubricated every 10 hours. Remove the belt cover plate (left side), exposing the idler ann and belt mechanisms. Remove the idler pulley (See Figure 5) to clean the shaft and pulley surfaces. Lubricate the shaft with several drops of SAE #30 oil, being sure not to get oil on the belt or outer pulley surfaces. Replace the cover.

SHAFT IDLER

PULLEY I

FIGURE 5

CHAPTER 111 BELT REPLACEMENT

BELT REMOVAL

Remove belt cover plate (left side) to gain access to belt and. idler mechanism. With the clutch lever in the neutral position, slip the belt off the engine pulley. Engage clutch handle to lift brake tab from auger pulley. Slip belt off auger pulley.

NEW BELT FINGER (610009) (MOUNT PARALLEL TO BELT) IN THE ENGAGED P

GUIDES BELT

AUGER PULLEY

FIGURE 6

BELT REPLACEMENT

Lift the brake tab from the auger pulley using the clutch control handle. Install the belt over the auger pulley. Release the clutch handle and slide the belt over the engine pulley. (See Figure 6.)

Note: The belt must be installed under the belt guides. Failure to do so will result in very early belt failure.

BELT GUIDE ADJUSTMENT Adjust the upper and lower belt guides to provide 1/16” clearance between the belt and the guide in the engaged position. Some adjustment is possible by loosening the nuts securing the belt guides. Extreme adjustment may be made by bending the belt guides; however, a severely stretched belt should be replaced.

BELT KEEPER KIT (Service Letter 79-119) If the unit has shown a tendency to throw belts off the auger pulley, adjust the idler pulley and brake tab as described in Chapter I. A belt keeper kit (OMC Part No. 610409) can be installed. It should be installed in place of the pivot washer with the tab parallel to the belt in the engaged position. (See Figure 6).

CHAPTER IV CONTROL MECHANISMS DEFLECTOR CONTROL The deflector control is serviced by replacement of the outer handle or the inner linkage. Be certain to route the inner shaft between the switch leads and the primer hose.

CHOKE CONTROL CABLE The choke control cable is retained at the rear engine mounting bolt and at the rear engine compartment cover. The choke must be adjusted to

provide full! choke when pulled out and no choke when p u s h in. Adjustment is accomplished by rotating the choke cable clamp under the rear engine mounting bolt. Do not slide the choke cable clamp up or; down the cable.

Adjust the cable in the fully open position with the upper section of the cable parallel to the main tubular handles. (See Figure 7.)

GOVERNOR The governor is designed to operate at a fixed speed, 4000 \ with the auger disengaged. Refer to SECTION 5 for adjusting instructions.

SAFETY WARNING: DO NOT ADJUST GOVERNOR TO A HIGHER ENGINE SPEED.

!

FIGURE 7

CARBURETOR CARBURETOR ADJUSTMENT The carburetor is a diaphragm-type incorporating an internal fuel pump. This pump is actuated by the alternating vacuum-pressure in the crankcase. The carburetor is serviced by a diaphragm kit (Part No. 681990) and a carburetor repair kit (Part No. 681989). There are three adjustments which must be made whenever the carburetor is serviced.

Diaphragm metering lever: (See Figure 8.) This lever is to be adjusted flush with the outer rim of the carburetor body casting. The lever is spring loaded. Be extremely careful not to stretch or distort this spring during diassembly and reassembly. Be certain that the lever return spring is seated in the recess in the carburetor body.

FIGURE 8

The presetting adjustment is one (1) turn off the seat €or high speed (short) needle valve. (Figure 2). The ‘low speed (long) needle valve (Figure 2) requires 1 1/4 turns off the seat. With unit running, the high speed (short) needle valve should be adjusted for maximum RPM and smooth running.

With the engine running at operating temperature, manually push the governor rod to slow the engine RPM to approximately 2,000 RPM. Releasing the governor rod should cause the engine to smoothly accelerate in RPM. If the engine stalls or hesitates in acceleration, it is set too lean.

If set too lean, the high speed needle valve should be opened approximately 1/8 turn at a time to correct this condition. Re-check acceleration between each adjustment until proper performance is obtained.

Note: Do not over-tighten the needle valves! This may cause damage to the needle tip as well as the seat.

Note: Whenever the carburetor is removed, be certain to check for proper choke operation.

CARBURETION PROBLEMS THAT YOU MAY EXPERIENCE.

a. Starts cold, but exhibits erratic running over a period of time. Carburetor adjustment requirements vary as the unit runs.

b. Starts cold and continues to run richer the longer it runs and cannot be corrected with a carburetor adjustment. May die rich.

During continued product testing, we have learned that the check valve in the primer fitting at the crankcase could be defective and allow “bleeding” of fuel directly into the transfer passage during operation. This results in a very “rich” condition and poor snow removal performance. Use an “easy-out” to remove the inner sleeve in the fitting. The spring and ball check can then be removed. Check valve number 487923 should then be installed as close to the primer as possible. The primer hose will need to be modified using “Ty-Rap” or hose clamps to eliminate any air leakage that may occur where the hose connects to the check valve. (Figure 1).

FIGURE 9

CUT PRIMER HOSE 2.5” FROM END NEAR PRIMER.

INSERT 487923 CHECK VALVE (CONE END POINTING TOWARDS NIPPLE)

IN LINE AND SECURE WITH CLAMPS.

PRIMER

2.5”

CHECK VALVE

RUBBER PRIMER HOSE 610587

FIGURE 1

CHAPTER V AUGER SERVICING The auger is serviced by replacement of the flight sections and the impeller tips. Remove all bolts which pass through the rubber sections and loosen

-all others for ease of servicing. Note that the impeller flight sections have a leading end and a trailing end. Be certain to install the flight sections with the square end pointing in the direction of rotation (See Figure 10).

DIRECTION OF ROTATION

SQUARE

FIGURE 10

AUGER REMOVAL AND REPLACEMENT

The auger is removed by removing all bolts securing the 2 halves together and the 4 self-tapping screws securing the impeller halves to the shaft hubs. Note the position of the halves on disassembly as they will fit together backwards. (See Figure 11.)

FIGURE 11 (FRONT VIEW)

CHAPTER VI ENGINE REMOVAL AND REPLACEMENT Remove both front and rear engine compartment covers.

SAFETY WARNING


Drain fuel tank. Remove the drive belt from the engine pulley. Remove the engine drive pulley. It may be necessary to use a soft hammer to break the pulley free from the crankshaft taper.

Remove the fuel line at the carburetor and the. primer hose at the crankcase. Remove the 2 switch leads from the engine.

Loosen the fuel tank mounting bolts to allow it to be pushed forward to clear the air baffle on the engine.

The engine may be removed with the muffler or separately. To remove the engine with the muffler,

remove the 4 hex nuts (See Figure 12) which secure the belt guides. Remove the screw securing the engine brace to the frame tube (See Figure 13). Pull the engine toward the center of the machine while swinging it backward and out of this frame.

To remove the engine separately, remove the 3 bolts securing the crankcase to the muffler. Swing the engine out in a similar manner.

Upon reassembly, be certain that the exhaust gasket is properly seated and that the choke cable is properly adjusted (refer to CHAPTER IV).

FIGURE 12

FIGURE 13


THEORY OF OPERATION

A battery produces an electric current by chemical action. A battery consists of one or more units called “cells.” Cells may be divided into two classes: primary and secondary (storage).

Cells used in flashlights, hearing aids, and portable radios are primary cells. They produce an electric current because of materials used in their construction. When all the chemical energy has been converted into electrical energy, the cell can no longer be used until new materials are added.

POSITIVE- PLATE

FIGURE 1

Secondary, or storage, cells have reversible actions known as "charge" and "discharge." A storage cell must first be charged by sending a current through the positive terminal from an outside source. On discharge, current passes through the cell in an opposite direction. When the cell provides a current, or discharges, it simply reverses the chemical reaction that takes place' during the charging period. An elec-* tric current (charge current) replaces the lost chemical energy before the cycle can s t a r t again.

The lead-acid battery used in Lawn-Boy mowers consists of six cells. (Figure 1.) The atoms in the electrolyte are neutral because they have an equal number of positive and negative charges. When electrolyte is dissolved in water, it splits into positive and negative ions. Positive ions have a defi- ciency of electrons. Negative ions have an excess of electrons. The positive plate is now attacked by the electrolyte (sulfuric acid) which picks up some electrons. The electrolyte acts as a carrier for these electrons to the negative plate and from there through the rest of the circuit.

During the charging process the chain reaction is reversed and electrons move through the electrolyte to ,the positive plate.

NEGATIVE PLATE

BATTERY SERVICE BATTERY STRUCTURE

COVER

FIGURE

The main parts of a battery are illustrated in figure 2.

BATTERY

The negative plate consists of a grid framework filled with a porous mass of lead. This spongy form of lead allows electrolyte to penetrate the negative plates freely for the life of the battery.

The positive plates are made up of a grid framework which is filled with a lead peroxide material.

No positive plate may touch a negative plate o r all plates in the cell will lose their stored energy. Therefore thin sheets of non- conducting material called separators a re placed between the plates.

The lead and lead peroxide plates are re- ferred to as the "active" materials of the battery. These materials cannot become active until they are covered by a diluted solution of sulfuric acid called "electrolyte." Sulfuric acid acts as a carr ier for the electric current within the battery.

13-2

PLATE

The battery container and cover a re both made of a durable plastic and are inactive to the corrosive electrolyte. Fil ler plugs a re designed to baffle gases, prevent loss of acid due to vibration and for filling cells to their proper level.

CHECKS Maintenance

MAINTENANCE AND SERVICE

NOTE Maintenance checks should be made regularly to assure good performance of the battery.

Maintenance checks should be made regularly to assure good performance of the battery. 1. Check fluid level in each cell and add

mineral free water if necessary. 2. Check terminals for dirt and grease. If

dirty or greasy remove cable clamps and clean terminals.

3. Check voltage of battery. If battery is no longer strong enough to start mower o r it is a hard starting mower, recharge battery.


REVISED 1977

4. To recharge battery, insert plug into charger jack. Plug trickle charger into 110 volt AC outlet, allowing battery to charge approximately ten hours.

NOTE

Do not charge for longer than 48 hours, as extended charge times will cause electrolyte to evaporate leaving a dry and damaged battery. Al- low battery to stand for some time after filling before placing on charge

5. When charging battery use only the LAWN-BOY charger supplied with the mower. Do not charge at a rate exceeding 1 amp.

Servicing

Specific Gravity of Battery

BATTERY SERVICE State of Charge Specific Gravity Reading

Fully Charged 1.265 75% Charged 1.225 50% Charged 1.190 25% charged 1.155 Discharged 1.120

1. Remove caps from battery using screwdriver.

2. Place hydrometer (part no. 681007) (see figure 3) into each cell. Squeeze bulb on top of hydrometer and release slowly.

3. Number of balls floating indicates condition of battery. If any cell reads two balls or less floating, recharge battery for 10 hours.

When using a hydrometer that shows specific gravity, the following specific gravity numbers (when measured at 80°F (26.7°C) indicate the approximate battery charge condition.

FIGURE 3


REVISED 1977

13-3

BATTERY SERVICE

For accuracy, the liquid level of the cells should be at normal height when a hydrometer reading is taken. Hydrometer readings should never be taken immediately after water has been added to battery or immediately after charging. Let stand for 20 minutes. Specific gravity of fully charged battery should be 1.265 with 80°F. (26.7ºC) electrolyte temperature.

SAFETY WARNING

Battery electrolyte is an acidic solution and should be handled with care. If electrolyte is spilled or splashed on any part of the body, immediately flush the exposed area with liberal amounts of water and obtain medical aid as soon as possible.

BATTERY CORROSION

The overflow of electrolyte causes many problems. Corrosion begins to form on the battery terminals and in battery box. Cor- rosion is a good conductor, causing a dra in on battery even when mower is not in use.

Corroded batteries, terminals and frames should be cleaned with a solution of four tablespoons of baking soda to a gallon of water.

2. Brush on the soda-water solution with a brush and flush clean with fresh water.

3. Coat terminal connections with petroleum jelly after reassembly to retard corrosion.

AGING BATTERIES

As batteries age, they progressively lose their ability to reach their rated full charge voltage and specific gravity. The first indication would be high water usage.

1. When this happens, charging time should be decreased from 10 hours to 8 hours, from 8 hours to 6 hours, etc., until battery's useful life has been spent.

2. When specific gravity readings, taken at one hour intervals, remain the same, the battery has all the charge it is capable of accepting.

3. If the level of voltage is too low for normal operation of mower, replace battery.

TESTING BATTERY FOR SERVICE,ABILITY INSTRUMENTS

Testing a battery for serviceability requires the use of instruments of unquestioned accuracy.

A Hydrometer should be graduated to read from 1.160 to 1.320 in graduations of ,005 specific gravity. The graduated markings should be not less than 1/16'' (1.6 mm) apart and accurate to within ,002 Sp. Gr. The graduated portion of the stem should be about 2 inches (50.8 mm) long. Clearance between float and barrel, at smallest diameter, should be a minimum of 1/8 inch (3.2 mm) around all sides.

A battery Thermometer should be of the mercury-in-glass type, have a scale reading as high as' 125°F. (51.6ºC), and be designed for not over a, 1-inch (25 mm) bulb im- mersion. A suitable dairy-type thermometer may prove satisfactory for the purpose.

SAFETY WARNING Shop electrical meters for battery testing should be accurate within 2 percent over

Do not use pressure gun greases on the entire scale range. Laboratory meters connections as some contain graphite, should be accurate within 1/2 of 1 percent which conducts electricity, and others over the entire scale range and should be will deteriorate battery sealer. of the permanent magnet moving coil type,


REVISED 1977

the voltmeter preferably being shielded from external magnetic fields.

A good Voltmeter should have a 3-volt scale in .02-volt divisions and be accurate to within 1% over full scale for measuring cell voltage and/or a scale covering 15 volts in .l-volt divisions for testing overall battery voltage. The resistance of a good voltmeter is at least 20,000 ohms per volt. A portable type D.C. voltmeter of at least 20,000 ohms per volt sensitivity, accurate to at least 1% and having a range of 150/ 15/3 volts would be satisfactory for accurate test work.

A portable type D.C. Ammeter accurate to at least 1 percent, with scale range of 50/25/10 amperes and used with an external 500 ampere shunt to obtain a 500 ampere range, would be satisfactory for accurate test work.

OPEN-CIRCUIT VOLTAGE BATTERY TESTERS

The open-circuit voltage of a battery will vary slightly with the specific gravity of the electrolyte in the individual cell. A sen- sitive voltmeter can therefore be provided with a scale which indicates equivalent specific gravity or s ta te of charge and can be used as a sort of "electrical hydrometer" under certain conditions. Such instruments must have a separate scale calibrated for each separate fully-charged gravity, or a correction factor must be used if the cells are adjusted to any other fully-charged gravity. For example, such O.C.V. meters, in order to be reliable, must either be used only on batteries and/or cells whose fully- charged gravity is that for which the instrument is calibrated, or be used with a correction factor of .01 volt equals .010 specific gravity.

Example: 1.265 Sp. Gr. 2.10 Volts/Cell 6.3 Volts/6-Volt Battery

12.6 Volts/12- Volt Battery

No temperature correction factor has to be applied to the gravities indicated by O.C.V. meters. However, the instruments cannot be used on batteries and/or cells which have just come off charge, as the gases held on the plates cause the instrument to give a falsely high reading. The instruments are useful for testing batteries in stock. Letting batteries stand on open circuit for several hours after charging will dissipate the gases from the plates and enable correct readings. to be obtained.

HIGH-RATE DISCHARGE EQUIPMENT

High-rate discharge equipment is available in a variety of forms. Most of these work on the principle of discharging the battery through a fixed resistance, for about 15 seconds, and measuring the battery and/or cell voltages while discharging a high rate to determine the cranking ability of the battery.

The tester meter must have 2% accuracy over the entire scale range(s). The tester should be capable of discharging the battery as a unit and measuring voltage as the criterion for passing or failing the battery.

BATTERY TESTING CHART

A step-by-step procedure based on hydrometer and voltmeter readings is shown in the "Battery Testing Chart". This chart will be helpful in rendering correct battery service.


REVISED 1977

BATTERY SERVICE

BATTERY TESTING CHAR

HYDROMETER TEST (80°F) (26.7°C)

(See Note "A" Below)

(2) Less than 1.215 Sp. Gr.

(3) Cells showing more than 50 points (.050 Sp. Gr.) variation in

(4) Battery or cells showing more than 1/2 charge.

(5) Battery showing less than 1/2 charge o r cells showing less than 1/2 charge but not more than .05 volt variation.

(6) If cell connectors are accessible, cells showing more than .05 volt variation.

STATE OF CHARGE OR BATTERY CONDITION

(1) Probably good.

(2) Questionable.

(3) A. Short circuit in low cell.

leakage or excessive overcharge.

C. Improper addition of acid o r contaminates.

D. Natural or premature failure.

E. Cracked box partition.

B. Loss of electrolyte by

(4) Probably good.

(5) Questionable.

(6) See No. 3 above.

NOTE: A For batteries having normal fully-charged spec 80°F, (2.67°C), the electrolyte level should be 1/4”

separators. Do not take readings soon after adding

CORRECTION OR REMEDY

(1) No correction required if variation among cells is not over -050 Sp. Gr. Make a thorough check of the electrical system for short circuits, loose connections, corroded terminals, etc.

(2) Battery should be recharged. After recharge repeat step No. 1. (See note "B.")

(3) Try to recharge battery (See note "B.") If .050 Sp. Gr. variation persists battery should be replaced. If battery accepts recharge and variation does not persist, repeat step No. 1.

(4) Apply remedy given for No.

(5) Apply remedy given for No.

1 above.

2 above.

(6) Apply remedy given for No. 3 above.

ic gravity of 1.265 o r above at 4" to 1/2" (6 to 13 mm) above ing water, but charge until solu-

tion is mixed. Hydrometer readings should be corrected for temperature if temperatures are very far from 80°F. (26.7°C).

consult manufacturer's recommendations.

For proper charging procedures refer to "Charging Storage Batteries," and consult charging equipment manufacturer's specifications.

NOTE: B For batteries with special fully-charged gravity and/or extra electrolyte space


REVISED 1977

BATTERY SERVICE

BATTERY REPLACEMENT AND STORAGE Battery Replacement

The dry charged battery is a battery containing charged plates in a dry condition.

Electrolyte and battery both are to be at room temperature (70°F to 80°F).

Fill battery with electrolyte (sulfuric acid and water) of 1.260 1.265 specific gravity. Battery is now approximately 75% fully charged. A fully charged battery should indicate 12.0 12.5 volts on a voltmeter.

2. After filling, charge battery for four hours using trickle charger. This will bring battery to full capacity.

SAFETY WARNING

Prior to filling battery with electrolyte, cut off sealed end of vent hose. Battery must vent. Lack of venting may cause battery to explode.

Battery Storage NOTE

When a customer has persistent battery trouble, suggest the following steps.

1. Before storage, battery should be thoroughly cleaned and brought up to full charge.

2. After charging, electrolyte level should be checked and brought up to the proper level by adding mineral free water.

3. Battery should be checked and brought up to full charge at no less than 30-day intervals.

4. Batteries should be kept in a cool, dry storage area. The cooler the temperature the less the self-discharge will be,

A fully charged wet battery, in good condition, can be stored at a temperature between +50° F and -10" F for a period of 4 to 5 months without damage. After this period it should be recharged for 8 to 10 hours. If storage temperature is above 50°F battery will need recharging every 30 days, and if temperature is above 100°F battery will need recharging every 15 days in order to maintain proper chemical balance.


REVISED 1977

BATTERY FAILURES BATTERIES

Figure 1 shows a good plate assembly. Figures 2 and 3 show the lead paste washed away from the grids. The paste is soft. Overcharging is one of the things that produces corrosion of positive grids and excessive gassing, which loosens active material in the plates, particularly the positive plates.

The loosened material will collect on the bottom as a fine brown sediment. Over- charging also causes excess loss of water and excessive gassing.

Figure 4 shows the paste extruding and shorting to an adjoining plate. FIGURE 1

FIGURE 3 FIGURE 4

BATTERY FAILURES Figure 5 shows the plates warped and part of a grid cracked and broken away.

Insufficient charging is one of the most common causes of buckling of the plates. Figure 5 shows some buckling (plates are curved). The lead sulfate occupies more space than the original material, and an excessive amount of it strains the plates.

Figure 6 shows a sulfated plate. Note the light colored corrosion. This material is lead sulfate. Large crystals or crusts of lead sulfate may form on the plates as a result of neglect or misuse. The excessive sulfation is difficult to reduce, and is in- jurious to the plates.

FIGURE 5

Sulfation can be the result of:

1. Allowing the battery to stand in a discharged condition for a considerable time.

water should have been used. 2. Filling the cells with electrolyte when

3. Operating the battery at excessive temperature (above 120°F).

4. Persistent undercharging.

The sediment deposited in the bottom is usually a fine white powder. This is prin- cipally lead sulfate.

FIGURE 6


BATTERY SERVICING D-400 SERIES BATTERY The battery is a 12 volt, DRY CHARGED battery designed specifically for Lawn-Boy mowers. PREPARING A BATTERY FOR SERVICE Remove fill plugs and add 19-1/2 ounces of electrolyte to upper level marks: Fill each cell to an equal level. Models equipped with a charger jack and plug require that the battery be installed on the mower before charging the battery. Allow battery to stand for 15 minutes before attaching trickle charger. DO NOT CHARGE AT A RATE EXCEEDING 1 AMP.

Connect the trickle charger to the battery before plugging it into a 110 volt outlet. Connect the plug to the charger jack (located in engine shroud on earlier models and in battery box on later models) before plugging the trickle charger into a 110 volt outlet.

Allow approximately 10 hours to obtain a complete charge. Add necessary fluid to maintain fluid level mark at the UPPER LEVEL MARKS. ASSEMBLING BATTERY TO MOWER

SAFETY WARNING

DO NOT ALLOW BATTERY TER- MINALS TO MAKE CONTACT WITH BATTERY COVER SUPPORT RODS.

With battery terminals facing the engine, insert battery into battery mounting bracket. Important: The battery must be mounted with the battery terminals facing the engine or the battery cover cannot be installed correctly. Do not operate without battery cover in place. With the battery inserted in the mounting bracket, insert battery overflow hose through drain hole in the mower housing. Cut Off excess length allowing 1 inch of hose to extend below the drain hole.

NOTE If vent hole is located on the right side of the battery, route overflow hose between the engine and the. battery. Insert thru the drain hole. Allowing 1 inch of hose to extend below mower housing. Cut hose a s required.

Connect battery leads to correct terminals: red to red positive), black to black (-, negative). Install the battery hold down strap (flat side down). Secure battery cover with acorn nuts and

TRICKLE CHARGER

POSITIVE "RED"

BATTERY

Place rear wheel adjustment lever in number 1 position. If lever rubs against battery cover, loosen battery bracket mounting bolts and move bracket until proper clearance is achieved.

13-10. SERVICE BULLETIN REFERENCES

REVISED 1977

BATTERY SERVICING D-400 SERIES

WIRING DIAGRAMS LEAD ACID BATTERY WIRING DIAGRAM-TWO POST SWITCH

BLACK LEAD FROM BATTERY TO TERMINAL MARKED “B” ON IGNITION SWITCH BLACK LEAD FROM ELECTRIC MOTOR TO TERMINAL MARKED 1".

ELECTRIC MOTOR

BLACK LEADS NEGATIVE

BATTERY

WIRING DIAGRAM FOUR POST SWITCH WIRE LEADS ATTACHED TO SWITCH AS FOLLOWS: GROUND "G” BLACK LEAD FROM ARMATURE PLATE GROUND SCREW

MAGNETO "M" BLACK LEAD FROM ELECTRIC MOTOR CAPACITOR IN ARMATURE PLATE

BATTERY “B” BLACK LEAD TO NEG. POST OF BAT.

START 'S" BLACK LEAD FROM ELEC. MOTOR

CHARGER JACK

BATTERY

-IGNITION SWITCH


BATTERY SERVICING D-600 SERIES 8330E-8231 E-8232E

WIRING DIAGRAM LEAD ACID BATTERY

TO MOTOR PLUG

BLACK TO "G" 679739 LEAD ASSEMBLY


NICKEL-CADMIUM AND SEALED LEAD ACID (S.L.A.)

BATTERIES SERVICING CAI !E

COVER REMOVED FOR ILLUSTRATION PURPOSES

In 1980 the Sealed Lead Acid (S.L.A.) 12 volt battery Part Number 682869 replaced the NI-CAD battery. The S.L.A. battery has 2.5 (A.H.) ampere hour capacity which provides more cranking power. The service care and maintenance requirements of this battery are different than the NI-CAD. Refer to pages 13-16 and 13-17 for this information.

MAINTENANCE

The Nickel-Cadmium (NI-CAD) battery Part Number 681359 is a 12 volt dry cell type with 1 (A.H.) ampere, hour capacity. This battery was first introduced on the self-charging (alternator) electric start models in 1975. Refer to pages 13-14 and 13-15 for NI-CAD battery service information.

a

SEALED. LEAD ACID BATTERY

NlCKEL =CADMIUM BATTERY SERVICING NICKEL- CADMIUM BATTERY PACK

SAFETY WARNING

DO NOT REMOVE THE NI-CAD BATTERIES FROM THE BATTERY PACK. THE BATTERY WILL ARC

ING INJURY OR FIRE. (EXAMPLE: RINGS, WATCHES AND METAL TABLES.)

ACROSS METAL SURFACES CAUS-

The NI-CAD battery pack consists of five sticks of two batteries each for a total of ten batteries connected together as shown. ICOVER REMOVED FOR ILLUSTRATION PURPOSES

The battery pack is shipped from the factory in an battery capacity has been shortened. uncharged condition.

SAFETY WARNING

TO PREVENT DAMAGE TO THE B A T T E R I E S , USE ONLY THE LAWN-BOY 100 M.A. (MILLIAMP) TRICKLE CHARGER WHEN CHARG- ING BATTERY PACK.

IF P R O P E R CHARGER IS NOT USED, DAMAGE MAY OCCUR TO THE BATTERY OR IT MAY EX- PLODE CAUSING INJURY TO YOU OR OTHERS.

NOTE:

Before placing the battery in service, it should be charged for a minimum period of 24 hours using the Lawn-Boy 100 M.A. (Milliamp) charger provided. Connect the charger to the battery then plug charger into 115 volt outlet. Voltage must be 12.3 volts or higher after completion of this procedure.

NI-CAD SATTERY MEMORY

If a NI-CAD battery has been subjected to a repea ted se r ies of par t ia l charge and partial discharge cycles of s imilar magni tudes, it may become so conditioned it will then deliver only slightly more voltage than has been required of it during the preceding repetitive cycles.

Thus, if the repeti t ive discharge cycles were short , it may appear as though the

Sometimes this conditioning is re fe r r ed t o as having a "memory." In order to remove th is memory and re turn the ba t te ry to near the original capacity, it must be deep discharged and then recharged.

If a NI-CAD battery is suspicious of this condition, it may be deep discharged by connecting a 12-volt automotive light bulb across the terminals and leaving it burn until the light goes out. It then can be recharged using the Lawn-Boy 100 M.A. tr ickle charger. Charge overnight for 12 hours. Do not apply a "quick" charge to the battery.

BATTERY MAINTENANCE

We recommend the following steps to main- ta in proper performance f rom the bat tery:


NICKEL-CADMIUM BATTERY SERVICING

12 Volt Nickel-Cadmium Battery Testing Procedures.

NOTE

Battery has to be out of service and disconnected from the charger for a minimum of 24 hours before testing.

1. Check battery voltage before charging.

2. Charge battery for a minimum of 24 hours.

3. Disconnect charger and let battery set for a minimum of 24 hours.

Battery Voltage must be 12.3 volts or higher after completion of this procedures.


SEALED LEAD ACID (S.L.A.) BATTERY WARRANTY

Open circuit voltage (0.C.V.) of all batteries r e ceived on warranty claims will be checked. If they register 11 .O volts or more when received and can be recharged, the warranty claim will be rejected and returned with the battery. If possible, battery should be placed on an electric start mower and checked for cranking ability.

Before returning a battery to the factory with a warranty claim because it "won't hold or take a charge," or "will not crank the engine," please refer to Section 13, pages 16 and 17 of the Lawn-Boy Service Manual for the testing procedures.

Step 1 Check battery voltage with a volt meter b e fore charging.

Step 2 -If the meter indicates an open circuit voltage (0.C.V.) of 11 .O volts or more, connect it to the Lawn-Boy charger for a period of 24 to 48 hours.

Step 3 Disconnect charger and let battery set for a minimum of 24 hours.

If battery voltage is 12.3 volts or higher after completion of this procedure, it should be returned to the customer for continued use. If possible, place it on an electric start mower and check for cranking ability.

If possible, the customer's battery charger should be checked. It should produce between 8 and 12 volts on a volt meter.

S.L.A. BATTERY

The Digital Multi Meter illustrated is available from the Lawn-Boy Service Department. It will check AC and DC voltage, AC and DC current, resistance, check diodes, amperes and continuity.

MODEL 8050 SOAR DIGITAL MULTI METER

13-16 SERVICE REFERENCE MANUAL REVISED 1983

SEALED LEAD ACID (S.L.A.) BATTERY SERVICING

SEALED LEAD ACID BATTERY PACK

SAFETY WARNING

DO NOT REMOVE THE SEALED LEAD ACID BATTERIES FROM THE BATTERY PACK. THE BATTERY

FACES CAUSING INJURY OR FIRE. (EXAMPLE: RINGS, WATCHES AND METAL TABLES.)

WILL ARC ACROSS METAL SUR-

The S.L.A. battery pack consists of six sealed cells connected together. Each cell contains electrolyte which is an acid solution. They are spill proof.

’ NOTE:

The S.L.A. battery will have a low charge when shipped from the factory.

NOTE

Before placing the battery in service, it should be charged for a minimum period of 24 hours (Do not exceed 48 hrs.) using the Lawn-Boy 100 M.A. (Milliamp) charger provided. Connect the charger to the battery then plug charger into 115 volt outlet. Voltage must be 12.3 volts or higher after completion of this procedure.

SAFETY WARNING

TO PREVENT DAMAGE TO THE BATTERIES, USE ONLY THE LAWN-BOY 100 M.A. (MILLIAMP) TRICKLE CHARGER WHEN CHARG- ING BATTERY PACK.

SEALED LEAD ACID BATTERY MAINTENANCE

Occasional charging may be required during the mowing Season if battery will not start the mower. If battery failure occurs, attach Lawn-Boy trickle charger supplied with mower, and charge for 10-12 hours.

NOTE NEVER LEAVE THE S.L.A. BAT- TERY ON CHARGER FOR MORE THAN 48 HOURS AS DAMAGE MAY RESULT.

S.L.A. BATTERY STORAGE NEVER STORE THE BATTERY IN A “RUN- DOWN” CONDITION. STORE BATTERY FULLY CHARGED (12-14 VOLTS) IN A COOL AREA.

Never place battery on cement surfaces during storage ie: garage or basement floor. Store battery on a wooden surface.

IF PROPER CHARGER IS NOT USED, DAMAGE MAY OCCUR TO THE BATTERY OR IT MAY EXPLODE CAUSING INJURY TO YOU OR OTHERS.

SERVICE REFERENCE MANUAL 13-17 REVISED 1983

SEALED LEAD ACID (S.L.A.) BATTERY SERVICING

12V 100 M.A. (milliamp) Charger (681369): Testing Procedures

Connect the V.O.M. (Volt-Ohm-Milliameter) as shown; be sure the polarity is correct. Plug in the charger to a 115V outlet. The meter reading should be between 8V to 12V DC.

12 Volt S.L.A. Battery Testing Procedures

Note: Battery has to be out of service and disconnected from the charger for a minimum of 24 hours before testing.

1. Check battery voltage before charging.

2. Charge battery for a minimum of 24 hours, but not more than 48 hours.

3. Disconnect charger and let battery set for a minimum of 24 hours.

Battery Voltage must be 12.3 volts or higher after completion of this procedure.


ALTERNATOR IDENTIFICATION

ALTERNATORS

Six different alternator assemblies will be found on , Testing procedures of all alternators are the same. the electric start Lawn-Boy mower since 1975. The Output specifications will vary between early and first was introduced on the 8233AE models with the later models. D-600 series engines.

PART NO. 681362 PART NO. 681563 PART NO. 682529

ALTERNATOR EARLY MODEL LATER MODEL RUBBER CONNECTOR ALTERNATOR ALTERNATOR

PLUG PLASTIC CONNECTOR 1982 AND LATER

D-600 SERIES F-100 SERIES F-100 SERIES

1975-76-77 PLUG 1978-79-80-81

PART NO. 683095 PART NO. 682719 PART NO. 683092

(LATE MODELS) SUPERCEDES 682719 SUPERCEDES 682529 WITH BLACK CONNECTOR

F-100 SERIES 1983 COMPLIANCE MODELS 1984 GRAY COLORED

WITH WHITE CONNECTOR GRAY COLORED 1981-82

NOTE

See page 13-21 for information and specifications on alternators used on 1983 and later models. SERVICE REFERENCE MANUAL. .13-19

REVISED 1983

ALTERNATOR TESTING

ALTERNATOR TESTING PROCEDURES

NOTE

To check output of all alternators, a milliameter with a capacity of 500 M.A. (mil- liamps) is required for testing.

1. Before testing output of the alternators, check the air gap and readjust to .010 if necessary.

SEE PAGE 13-21 FOR SPECIFICATIONS OF EACH ALTERNATOR.

2.

3.

To check output of the alternator accurately, it is necessary to run the engine between 3100 and 3300 R.P.M. Readjust the governor if necessary.

Before attaching milliameter leads start the engine. Run at high speed R.P.M. 3100-3300

4. With the engine running disconnect the plug from the battery. Reverse the plugs and reconnect as shown. Attach meter leads. Be sure polarity is correct.

NOTE

With meter leads attached DO NOT

ENGINE ELECTRICALLY. If the starter is activated irreparable damage to meter will occur.

STOP AND THEN RE-START

4 BLACK WIRES

TO MOWER To Battery

\ MILLIAMETER

13-20. .SERVICE REFERENCE MANUAL REVISED 1983

ALTERNATOR TESTING 5. Milliampere (M.A.) output specifications for

each alternator is:

D-600 Series Part No. 681362

F-100 Series (Early Models),

Part No. 681653

F-100 Series (Late Models)

Part No. 682529 Millimeter readings should be between:

70-120 M.A. 70-120 M.A. 200-450 M.A.

Volt meter readings should be between: 1.2-1.5 volts 1.2-1.5 volts 140-160 volts

F-100 Series 1983 Compliance Models 1984 Gray Colored (Late Models) Part No. 682719 Part No. 683092

Part No. 683095 Supercedes 682719 (Supercedes 682529) With Black Connector

With White Connector Millimeter readings should be between:

Volt meter readings should be between: 200-450 M.A. 200-450 M.A. 200-450 M.A.

18-32 volts 140-160 volts 18-32 volts 4 BLACK WURES

6. To check voltage output for the alternator proceed as follows. Start and run engine at 3200 TO MOWER RPM. TO BATTERY CASE

7. With engine running, disconnect wiring harness plug from battery. Connect leads from volt meter to connector plug as shown. Be sure METER

polarity is correct. Refer to the voltage requirements listed above for each alternator.

SERVICE REFERENCE MANUAL REVISED 1983

TROUBLE SHOOTING THE ALTERNATOR PART NO. 681 362 CHARGING SYSTEM

MODEL 8233AE, 8234AE & 8235AE D-600 SERIES

STARTER DOES NOT TURN ENGINE: BATTERY RUN DOWN BATTERY VOLTAGE BELOW 10 VOLTS Alternator Not Charging Battery run down. The resistance on the pins of plug “H” should read LOW

with V.O.M. leads in one direction and HIGH with leads reversed. (Meter on RX 1) . This checks for bad diodes. A low resistance or high resistance in both directions indicates defective diodes. The output voltage of plug “E” with the engine running on: Normal (high) speed 1.2 to 1.5 Volts (Using a 20,000 ohms per volt meter)

Ground Wire “M” Open Check resistance at plug “E”. With the’ self-propelled handle in neutral, and or Loose the key switch in the ‘START’ position, and plugs “G” & “H” disconnected,

the circuit reads: A GOOD CIRCUIT READS SHORTED A BAD CIRCUIT READS HIGH RESISTANCE (METER ON RX 1)

Key Switch Defective Key switch in the ‘START’ position. A good switch reads SHORTED on terminals 2 & 3. A bad switch will read 1 or more ohms. (Meter on RX 1 )

Starter Motor Defective Check voltage at starter plug “A” when key switch is in ‘START’ position. Voltage is to be above 10 volts. The resistance between the terminals on plug “B” should read approximately .3 ohms resistance for a good motor. (Meter on RX 1 ) Turn motor for lowest reading.

Self-propelled Interlock When the self-propelled handle is in neutral, the interlock switch should be Switch Open closed. A good switch reads SHORTED on the pins of plug “D”. (Meter on

RX 1 )

Short Circuit Battery run down. The resistance on pins of plug “E” (with all other plugs connected, self-propelled in neutral, and, key switch in “off” position) should read as follows:

With volt-ohmeter on RX 1 the low reading will be between 15 ohms and 20 ohms. With the volt-ohmeter on its highest setting, the high reading will be MEG ohms.

Alternator Diodes Battery run down. Disconnect plugs “A”, “C” and “J”. Connect a 20,000 Leaking ohms per volt volt meter as follows:

Use 15 volt D.C. scale (Min.). Disconnect plug “E”. Reconnect plug “E” so that the male pin of plug “E” and the female of plug “F” are not connected. Connect the positive lead of the volt meter to the male pin of plug ‘‘E”. Connect the negative lead of the volt meter to the female of plug “F”. The meter should read zero. A reading of more than one volt indicates excessive leakage which could run the. battery down during storage.

____-- __-

ENGINE STOPS WHEN KEY SWITCH IS IN ‘RUN’ POSITION: Key Switch Defective Key in ‘RUN’ position, the resistance between terminals 1 & 2 on plug “ K ”

reads less than 1 MEG ohm. ENGINE DOES NOT STOP IN KEY IN ’OFF’ POSITION:

Key Switch Defective Key on ‘OFF’ position, the resistance between terminals 1 & 2 on plug “ K ” reads INFINITE resistance. (Meter on RX 100)

Ground Lead “M” Open Check terminal 2 on plug “J” to engine. If the resistance reads INFINITE at Ground the ground is bad. (Meter on RX 100) Connection at “L” Open Lead disconnected.

13.22. .SERVICE REFERENCE MANUAL REVISED 1983

ELECTRIC START SERVICING D-600 SERIES WIRING DIAGRAM NICKEL CADMIUM BATTERY

LOCKOUT SWITCH STARTER

KEY SWITCH

FIGURE KEY IN “OFF” POSITION


C.D.

FIGURE

LOCKOUT SWITCH

2 KEY IN ‘START’ POSITION

ST C.D.

IGNITION A

SERVICE REFERENCE FIGURE 3 KEY IN "RUN" POSITION

MANUAL 13-23 REVISED 1983

TROUBLE SHOOTING THE EARLY MODEL F - l o 0 SERIES ALTERNATOR CHARGING SYSTEM PART NO. 681653

STARTER DOES NOT TURN ENGINE:

BATTERY RUN DOWN

Alternator or Charger Not Charging

Ground Wire “ M ” Open or Loose

Key Switch Defective

Starter Motor Defective

Self-propelled Interlock Switch Open

Short Circuit

Alternator Diodes Leaking

REFER TO BATTERY TEST PROCEDURES

Battery run down. The resistance on the pins of plug “H” should read LOW with V.O.M. leads in one direction’ and HIGH with leads reversed. (Meter on RX 1). This checks for bad diodes. A low resistance or high resistance in both directions indicates defective diodes.

The output voltage of plug “E” with the engine running on: High speed 1.2 to 1.5 Volts (Using a 20,000 ohms per volt meter)

Check resistance at plug “E”. With the self-propelled handle in neutral, and the key switch in the ‘START’ position, and plugs “G” & “H” disconnected, the circuit reads:

A GOOD CIRCUIT READS SHORTED A BAD CIRCUIT READS HIGH RESISTANCE (METER ON RX 1)

Key switch in the ‘START’ position. A good switch reads SHORTED on terminals 2 & 3. A bad switch will read 1 or more ohms. (Meter on RX 1)

Check voltage at starter plug “A” when key switch is in ‘START’ position. Voltage is to be above 10 volts. The resistance between the terminals on plug “B” should read approximately .3 ohms resistance for a good motor. (Meter on RX 1) Turn motor for lowest reading. When the self-propelled handle is in neutral, the interlock switch should be closed. A good switch reads SHORTED on the pins of plug “D”. (Meter on RX 1) Battery run down. The resistance on pins of plug “E” (with all other plugs connected, self-propelled in neutral, and key switch in “off” position) should read as follows:


Battery run down. Disconnect plugs “A” , “C” and “J”. Connect a 20,000 ohms per volt volt meter as follows:

Use 15 volt D.C. scale (Min.). Disconnect plug “E”. Reconnect plug “E” so that the male pin of plug “E” and the female of plug “F” are not connected. Connect the positive lead of the volt meter to the male pin of plug “E”. Connect the negative lead of the volt meter to the female (-) of plug “F”. The meter should read zero. A reading of more than one volt indicates excessive leakage which could run the. battery down during storage.

-___-

_I.__

ENGINE STOPS WHEN KEY SWITCH IS IN ‘RUN’ POSITION: Key Switch Defective Key in ‘RUN’ position, the resistance between terminals 1 & 2 on plug “K”

reads less than 1 MEG ohm.

ENGINE DOES NOT STOP WITH KEY IN ‘OFF’ POSITION: Key Switch Defective

Lead disconnected. Connection at “L” Open the ground is bad. (Meter on RX 100) at Ground Check terminal 2 on plug “J” to engine. If the resistance reads INFINITE Ground Lead “M” Open

Key in ‘OFF’ position, the resistance between terminals 1 & 2 on plug “K” reads less than 1 MEG ohm.

-I--

13-24 ;SERVICE REFERENCE MANUAL REVISED 1983

STARTER WIRING DIAGRAM

(USING 681653 ALTERNATOR) (LOW OUTPUT) F-100 SERIES (EARLY MODELS)


C.D. IGNITION

WHT-BRN

FIGURE 1 KEY IN "OFF" POSITION

LOCKOUT SWITCH STARTER C.D.

ONLY

ALTERNATOR

FIGURE 2 KEY IN "STAR'T" POSITION

RED-BLK KEY SWITCH

WHT-BRN

RED-BLK

KEY SWITCH


ONLY

ALTERNATOR RED-ELK

KEY SWITCH

FIGURE 3 KEY IN "RUN" POSITION


TROUBLE SHOOTING THE LATER MODEL F-100 SERIES

PART NO. 682529 HIGH OUTPUT ALTERNATOR CHARGING SYSTEM

STARTER DOES NOT TURN ENGINE:

BATTERY RUN DOWN


Ground Wire “M” Open or Loose




Short Circuit



Battery run down. The resistance on the pins of plug “H” should read LOW with V.O.M. leads in one direction and HIGH with leads reversed. (Meter on RX 1). This checks for bad diodes. A low resistance or high resistance in both directions indicates defective diodes. The output voltage of plug “E” with the engine running on: High speed 140 Volts 160 Volts (Using a 20,000 ohms per volt meter)




Check voltage at starter plug “A”’when’ key switch is in ‘START’ position. Voltage is to be above 10 volts. The resistance between the terminals on plug “B” should read approximately .3 ohms ‘resistance for a good motor. (Meter on RX 1) Turn motor for lowest reading. When the self-propelled handle is in neutral, the interlock switch should be closed. A good switch reads SHORTED on the pins of plug “D”. (Meter on RX 1)

Battery run down. The resistance on pins of plug “E” (with all other plugs connected, self-propelled in neutral, and key switch in “off” position) should read as follows:


Battery run down. Disconnect plugs “A”, “C” and “J” Connect a 20,000 ohms per volt volt meter as follows:

Use 15 volt D.C. scale (Min.). Disconnect plug “E”. Reconnect plug “E” so that the male pin of plug “E” and the female of plug “F” are not connected. Connect the positive lead of the volt meter to the male pin of plug “E”. Connect the negative lead of the’ volt meter to the female ( - ) of plug “F”. The meter should read zero. A reading of more than one volt indicates excessive leakage which could run the. battery down during storage.

ENGINE STOPS WHEN KEY SWITCH IS IN ‘RUN’ POSITION: Key Switch Defective Key in ‘RUN’ position, the resistance between terminals 1 & 2 on plug “K”

reads less than 1 MEG ohm. I ENGINE DOES NOT STOP WITH KEY IN ‘OFF‘ POSITION:

terminals 1 & 2 on plug “K”

resistance reads INFINITE



F-100 SERIES (LATER MODELS THRU (USING 682529 ALTERNATORS) (HIGH

LOCKOUT,

1982) OUTPUT)

SWITCH STARTER C.D.

SELF PROPELLED. ONLY

ALTERNATOR

FIG FIGURE 1 KEY IN "OFF." POSITION


SELF

ALTERNATOR

FIGURE 2 KEY IN "START" POSITION


SELF PROPELLED ONLY

ALTERNATOR

FIGURE 3 KEY IN -RUN- POSITION

WHT-BRN

RED-BLK

KEY SWITCH

WHT-BRN

RED-BLK

KEY SWITCH

WHT-BRN

RED-BLK

KEY SWITCH

TROUBLE SHOOTING-THE MODEL F-100 SERIES ALTERNATOR CHARGING SYSTEM PART NO. 683095

WITH WHITE CONNECTOR STARTER DOES NOT TURN ENGINE:

BATTERY RUN DOWN






Short Circuit



Battery run down. The resistance on the pins of plug “H” should read LOW with V.O.M. leads in one direction and HIGH with leads reversed. (Meter on RX 1). This checks for bad diodes. A low resistance or high resistance in both directions indicates defective diodes.

(Using a 20,000 ohms per volt meter)


A GOOD CIRCUIT READS SHORTED

RESISTANCE (METER ON RX 1) A BAD CIRCUIT READS HIGH


Check voltage at starter plug “A” when key switch is in ‘START’ position. Voltage is to be above 10 volts. The resistance between the terminals on plug “B” should read approximately .3 ohms resistance for a good motor. (Meter on RX 1) Turn motor for lowest reading. When the self-propelled handle is in neutral, the interlock switch should be closed. A good switch reads SHORTED on the pins of plug “D”. (Meter on RX 1)


With volt-ohmeter on RX 1 the low reading will be between 15 ohms and 20 ohms. With the volt-ohmeter on ‘its highest setting, the high reading will be MEG ohms.

Battery run down. Disconnect plugs “A”, “C” and “J”. Connect a 20,000 ohms per volt volt meter as follows:


ENGINE STOPS WHEN KEY SWITCH IS IN ‘RUN’ POSITION:. Key Switch Defective Key in ‘RUN’ position, the resistance between terminals 1 & 2 on plug “K”

reads less than 1 MEG ohm.

ENGINE DOES NOT STOP WITH KEY IN ‘OFF’ POSITION: 1 & 2 on plug “ K ”

resistance reads INFINITE



F-100 SERIES WITH ALTERNATOR PART NO. 683095 WITH WHITE CONNECTOR

.LOCKOUT SWITCH

ALTERNATOR

KEY SWITCH

FIGURE 1 KEY IN "OFF'” POSITION


IGNITION

ONLY

ALTERNATOR

fIGURE 2 KEY IN "START" POSITION

ALTERNATOR


ONLY

WHT-BRN

RED-BLK KEY SWITCH

WHT-BRN

RED-BLK

KEY SWITCH


TROUBLE SHOOTING THE MODEL F-100 SERIES ALTERNATOR CHARGING SYSTEM PART NO. 6,83092

WITH BLACK CONNECTOR STARTER DOES NOT TURN ENGINE:

BATTERY RUN DOWN Alternator or Charger Not Charging





Short Circuit


ENGINE STOPS WHEN


Battery run down. The resistance on the’ pins of plug “H” should read LOW with V.O.M. leads in one direction and HIGH with leads reversed. (Meter on RX 1). This checks for bad diodes. A low resistance or high resistance in both directions indicates defective diodes. The output voltage of plug “E” with the engine running on: High speed 18 Volts 32 Volts (Using a 20,000 ohms per volt meter)



Key switch in the ‘START’ position. A good switch reads SHORTED on terminals 2 & 3. A bad switch will read 1 or more ohms. (Meter on RX 1) Check voltage at starter plug “A” when key switch is in ‘START’ position. Voltage is to be above 10 volts. The resistance between the terminals on plug “B” should read approximately .3 ohms resistance for a good motor. (Meter on RX 1) Turn motor for lowest reading. When the self-propelled handle is in neutral, the interlock switch should be closed. A good switch reads SHORTED on the pins of plug “D”. (Meter on RX 1)



Battery run down. Disconnect plugs “A”, “C” and “J”. Connect a 20,000 ohms per volt volt meter as follows:


KEY SWITCH IS IN ‘RUN’ POSITION: Key Switch Defective Key in ‘RUN’ position, the resistance between terminals 1 & 2 on plug “K”

reads less than 1 MEG ohm. I ENGINE DOES NOT STOP WITH KEY IN ‘OFF’ POSITION:

1 & 2 on plug “K”

resistance reads INFINITE at Ground



WITH BLACK CONNECTOR F-100 SERIES WITH ALTERNATOR, PART NO. 683092

ALTERNATOR


C.D.

SELF

ALTERNATOR

FIGURE 1 - KEY IN "OFF" ,POSITION


ONLY

I BROWN

ALTERNATOR BLK

FIGURE 2 KEY IN “START” POSITION


WHT-BRN

RED-BLK

KEY SWITCH

WHT-BRN

RED-BLK KEY SWITCH

C.D.

WHT-BRN

ALTERNATOR RED-BLK

KEY SWITCH

FIGURE 3 KEY IN "RUN" POSITION


PREPARING BATTERY FOR SERVICE

The Power Pack contains three twelve- volt lead-acid batteries connected in ser ies to provide thirty-six volts of power to electric motor. Each battery has a nine ampere hour rating. The battery i s shipped from the factory in a dry-charged condition, Prior to filling battery with electrolyte, cut vent hose so approximately 4-1/2 inches remain on the battery.

Remove battery filler caps and slowly fill each cell equally (six per battery) with electrolyte. Observe electrolyte level fluid must be equal in all cells and between two yellow lines on battery case. Total electrolyte capacity in each battery .is approximately 19-1/2 fluid ozs. DO NOT OVER- FILL battery or acid will drain out during charging period, damaging power pack and batteries. Reinstall filler caps.

NOTE

AFTER BATTERY IS FILLED WITH E L E C T R O L Y T E IT IS 75%

DLED WITH CARE. DO NOT SHORT TERMINALS.

CHARGED AND SHOULD BE HAN-

SAFETY WARNING

ELECTROLYTE CONTAINS SUL- FURIC ACID. IT CAN CAUSE SEVERE BURNS AND DAMAGE TO SKIN, CLOTHING, ETC. IF ELEC- TROLYTE IS SPILLED, FLUSH CON- TAMINATED AREA IMMEDIATELY AND THOROUGHLY WITH WATER.

CHARGING BATTERIES

Place each battery in power pack and connect wiring as shown on decal inside top cover of power pack. Check for loose screws, cleanliness of power pack, and make certain vent hoses are not kinked or pinched.

SAFETY WARNING

BATTERIES COULD R U P T U R E DURING CHARGING CYCLE IF VENT SYSTEMS ARE BLOCKED.

Close power pack cover and secure top with two screws. Attach Lawn-Boy 36 volt battery charger to power pack.

The 'Lawn-Boy 36 volt battery charger is designed to charge all three batteries .in the power pack at the same time. DO NOT USE IT TO CHARGE OTHER BATTERIES OR TO INDIVIDUALLY CHARGE A BATTERY.

Set timer on charger in stand-by position. Plug charger into 115 V wall outlet.

Charger has a built in timer. Turn charger ON by turning timer -knob clockwise until arrow points to CHARGE. DO NOT GO BE- YOND WHITE DOT. This sets time for a full twelve hour charge. On the control panel a red INDICATOR LIGHT will come on indicating that batteries are receiving charge. The INDICATOR LIGHT will become very dim when fully charged. Once the charger has completed timed 12 hour charge cycle, it automatically sets itself to maintain a small trickle charge to "float" batteries in a fully charged condition.

SAFETY WARNING

Always disconnect charger from 115 V wall, outlet before connecting o r disconnecting charger from battery pack.

13-32. .SERVICE REFERENCE MANUAL

CORDLESS ELECTRIC SERVICING MODELS ;5800, 5801,5802 CHECKING BATTERY PACK

A fully charged battery pack should indicate between 36 38.5 volts on a voltmeter. If the reading obtained is less than 36 volts check each battery individually. A fully charged battery should register 12 12.5 volts with a specific gravity of 1.260 1.280. If one battery registers LESS than the other two, and bat ter ies are less than six months old, replace battery.

NOTE If a new battery is installed with two older and weaker batteries, the older batteries will "drag" the new one down, resulting in shortened battery life.

NOTE

See pages 13-1 thru 13-9 for additional information concerning lead acid batteries.

CHECKING LAWN-BOY CHARGER The Lawn-Boy cordless mower charger is a demand-type charger with a built in-timer Placing the timer knob in "charge" position allows for a full twelve hour charging period. Once the charger has completed the timed cycle, it automatically allows a small trickle charge to maintain batteries in a fully charged condition. To determine if charger is functioning properly, plug into a 115 V outlet. Place voltmeter on 50 V scale and check output at connector. If meter indicator moves in wrong direction, reverse the voltmeter leads in the connector. If charger is func-

\

CHECKING BATTERY PACK WITH VOLTMETER

tioning properly a reading between 36 50 volts W i l l be obtained.

When the charger is connected to the battery pack, the red light on the panel should be very bright, then become dim o r go out when it reaches the stand-by position. If the red light DOES NOT come on when turned to the charge position and you know there is 115V power at the outlet the charger is defective. If the light is still bright when placed in the stand-by position the charger is not functioning properly and will boil the batteries dry. If the timer knob does not move clockwise from the charge position, the batteries will boil dry. If the red light goes dim (or out) quickly (after ;turning charger on) this indicates a fully charged battery pack and the dimming of the 'light shows that the charger circuitry is properly controlling charge rate.

D.C. VOLTMETER AC 1 15V OUTLET 20K OHMS/VOLT

SERVICE REFERENCE MANUAL.. .13-33

CORDLESS ELECTRIC SERVICING MODELS 5800, 5801, 5802 SOLENOID

The solenoid controls high amperage current used to operate motor and blade braking circuit. It requires 24 volts to activate solenoid. To check solenoid, start motor, turn key to "OFF" position. If blade does not stop rotating within four seconds, solenoid is defective replace solenoid. To check solenoid resistance connect an ohmmeter across the terminals. The reading obtained should be between 130 140 ohms. If reading is not within specified range, replace solenoid.

CIRCUIT BREAKER A 20 amp circuit breaker protects the motor against a locked rotor condition, preventing motor from burning out.

On model 5800 the circuit breaker is located under the solenoid. On models 5801 and 5802 the circuit breaker is located in the battery box.

To check resistance, set ohmmeter on RX1 scale, and connect leads across circuit breaker. The reading obtained should be zero. High readings indicate an open condition. Replace circuit breaker as required.

CHECKING SOLENOID

CHECKING CIRCUIT BREAKER


WIRING DIAGRAM MODEL 5800

BLACK I

BAT.

I

GE

I

BAT.

I

BAT.

+

BREAKER

' I ' I J

ORANGE

I n BLACK START

RUN GREEN

SWITCH OFF

I

BLACK

SERVICE REFERENCE MANUAL

WIRING DIAGRAM MODELS -5802 5801

I BLACK

BATTERY

I L BATTERY

BATTERY

+

KEY SWITCH

BREAKER

I I I

I I

BLACK

I SOLENOID

BLACK

MOTOR

!

13-36.. .SERVICE REFERENCE MANUAL

L

X

n

J

SERVICE REFERENCE MA

NU

AL..

.13-37

110 VOLT ELECTRIC MOTOR SERVICING The electric motor used on Lawn-Boy electric mowers is specially designed for mower usage. It is a high-torque D-C motor working off of full wave rectified A-C. It is totally enclosed, fan-cooled, and is equipped with sealed ball bearings.

A magnetically activated brake, integral with the frame, serves to bring thecombined mass of the armature and mower blade to a stop when power is turned off. When power is on, diodes rectify A-C to D-C which is f e d to the field winding. The resulting magnetic field attracts the brake disc, moving it away from the brake surface on the armature fan and allowing the armature to rotate. Springs automatically apply the brake when power is turned off and the magnetic field collapses.

Servicing of the motor is limited to replacement of certain worn parts and assem- ? blies. Support the motor on the motor end bell (1, figure one). To gain access to the brushes, remove screws (6) and pull off top end bell (7).

To remove the armature (8), invert the motor and pull off the end bell. Carefully pull armature out of stator assembly (19). If defective, pull bearing (8) off armature using a bearing puller. Remove screw (4) and plate (3) to gain access to bearing (2).

Always replace worn brushes as a se t with the two in the repair kit. Items 16, 17, and 18 are available as a kit should the brake disc require replacement. See Parts Catalog for part numbers.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Motor End Bell Output End Bell Bearing Retainer Plate Bearing Retainer Plate Screw Armature Thrust Spacer Motor Assembly Screw Top End Bell Armature Assembly Commutator End Bearing I Thrust Spacer Stop Spring Rectifier Plate Assy. Brush Spring 16. "E" Ring Screw 17. Brake Spring Lockwasher 18. Brake Disc Brush 19. Stator Assy.

I

94288

Figure 1. Electric Motor Exploded View

13-38 SERVICE REFERENCE MANUAL

110 VOLT ELECTRIC MOTOR SERVICING A. BRUSH LENGTH

If brush length is less than 0.65", replace them. Otherwise, commutator surface will become burned and rough.

B. HOW TO CHECK.

NOTE: 1) Use ohmmeter. Never use megger, 'or diode will be destroyed. 2) As for Diode Test, change prod test leads of ohmmeter each other which

means (+) test lead is connected to (-) terminal of ohmmeter and (-) lead to (+) terminal.

3) Lift brushes so a s not to touch comutator.

I Diode Test

1) Place test (+) lead on A terminal, and (-) lead on C & D diode plate respec-

2) Place test (-) lead on A terminal, and (+) lead on C & D diode plate respec-

3) Place test (+) lead on B terminal, and (-) lead on C & D diode plate respec-

4) Place test (-) lead on B terminal, and (+) lead on C & D diode plate respec-

If diode is conductive in one direction for each item, it is normal. If diode is non-conductive in both directions for each item, it is open. If diode is conductive in both directions for each item, it is shorted.

tively.

tively.

tively.

tively.

I1 Testing Shunt Field Winding for Open Circuit

If resistance between C & D is about 123 ohms, shunt field winding is normal.

I11 Testing Shunt Field Wiring for Ground

Place prod test lead on E, and another lead on C and D diode plate respectively.

If test shows infinite resistance, shunt field winding is normal.

IV Testing Series Field Winding for Open Circuit

If resistance between D and E is about 0.2 ohm at 68°F, series field winding is normal.

SERVICE REFERENCE MANUAL 13-39

110 VOLT ELECTRIC MOTOR SERVICING

I

V Testing Series Field Winding for Ground d

If resistance between E and F is infinite, series field winding is normal.

VI Testing Armature Winding for Open Circuit

If resistance between G & H is about 0.5 ohm at 68°F, armature winding is normal.

VII Testing Armature Winding for Ground

If resistance between G and armature shaft is infinite, armature winding is normal.


SECTION 14 TOOLS SPECIAL ITEMS PISTON STOP

USED ON ALL MODELS OF LAWN- BOY ENGINES.

PART NO. 426814

Used to hold flywheel in place while loosening or tightening flywheel nut.

Remove spark pug and install piston stop. Screw finger-tight in spark plug opening.

CRANKSHAFT GUIDE

USED ON LAWN-BOY MODEL “C” D-400, D-500, D-600 SERIES ENGINES.

PART NO. 602887

Shown used to remove the armature plate and bearing assembly. Hold loose needles in bearing race on “ D ’ Series Engines.

I Shown used to reassemble the armature plate and bearing. Protects oil seals on both “C” and “D” Series Engines.

“D” SERIES

GOV RNOR ADJUSTING GAUGE I

USED ON D-400, D-500 AND D-600 SERIES ENGINES.

PART NO. 604541 I

Used ’to adjust governor lever on “D” Series Engines only.

“C” SERIES

GOVERNOR ADJUSTING GAUGE

PART NO. 602885

Used to adjust governor lever on “C” Engines only.

Series


SECTION 14 TOOLS SPECIAL ITEMS AIR GAP GAUGE

USED ON “D” AND “F” SERIES ENGINES

PART NO. 604659

.010 thick gauge to adjust air gap between flywheel magnet and heels of laminations on ignition coils, C.D. pack and alternator assemblies.

AIR GAP FLYWHEEL GAUGE

NO. 604659

TEST PLUG

PART NO. 426814

USED ON ALL LAWN-BOY ENGINES.

Remove spark plug from engine. Used to check function and output of ignition systems.


SECTION 14 TOOLS SPECIAL ITEMS TOOL DRIVER HANDLE

PART NO. 378737 :

Used with tools 605081, and 605082.

BEARING REMOVER

USED ON D-400 AND D-600 SERIES ENGINES.

Used with Driver, Part No. 378737 and soft hammer to drive old bearing out from the top towards bottom of the armature plate.

BEARING INTALLER

USED ON D-400 AND D-600 SERIES ENGINES.

PART NO. 605081

Use with Driver, Part No. 378737 and soft hammer to install new bearing in m a - ture plate. Drive from bottom towards top of m a t u r e plate until Bearing Installer bottoms on armature plate face. Always drive bearing into plate with “lettered” end of bearing cage positioned against head of tool.

14-4 SER VICE BULLETIN REFERENCES

SECTION 14 TOOLS

COMPRESSION PLIERS

PART NO. 303857


To remove the wrist pin retaining rings from pistons.

SPECIAL ITEMS

RING COMPRESSOR

USED ON c AND D SERIES ENGINES PART NO. 426020 Stagger ring and gaps, liberally coat cylinder walls, piston skirt and rings with oil and clamp rings with Ring Compressor. Slipping cylinder over rings while they are being held in this manner eliminates ring breakage and damage to piston, and cylinder.


WRIST PIN TOOL

PART NO. 602884


: Used to remove and assemble wrist pins in pistons.

SECTION 14 TOOLS SPECIAL ITEMS NOTE: “F” Series only.

CRANKSHAFT SUPPORT GAUGE

PART NO. 609968

“F” Series Only Correctly positions crankshaft support’ to crankshaft cover during reassembly.


SEAL INSTALLER

PART NO. 608976

USED ON ALL “C”, “D” AND “F” SERIES LAWN-BOY ENGINES.

Used to install upper and lower main bearing seals.


SECTION 14 TOOLS SPECIAL ITEMS To replace bearing, press out damaged or worn bearing with special Lam-Boy removal tool, part number 608361, and press in replacement with special installer tool, part number 608360.

NOTE

Do not drive bearings in or out. They must be removed or replaced using arbor press as illustrated.

BEARING REMOVER

PART NO. 608361

Used to remove bearings from diecast transmission housings on gear drive models.

BEARING INSTALLER

PART NO. 608360

Used to install bearings in diecast transmission housings.


SECTION 14 TOOLS’ SPECIAL ITEMS

FLEX HONE

PART NO. 609765

USED ON “C”, “D” AND “F” SERIES LAWN-BOY ENGINES.

Used to break the glaze on cylinder walls.

NOTE:

For use in slow speed and reversible drill for 5-7 strokes in each direction. USE WITH OIL.

UNIVERSAL ENGINE HOLDING FIXTURE

PART NO. 681865

Special engine holding fixture for C, D, and F Series Lawn- Boy engines.


SECTION 14 TOOLS SPECIAL ITEMS HYDROMETER (BATTERY TESTER)

FOR ALL LAWN-BOY WET CELL BATTERIES

PART NO. 681007

State of Charge Specific Gravity Reading

Fully Charged 1.265 75% Charged 1.225 50% Charged 1.190 25% Charged 1.155 Discharged 1.120

1. Remove caps from battery using screwdriver.

2. Place hydrometer (part no. 681007) (see figure 3) into each cell. Squeeze bulb on top of hydrometer and release slowly.

3. Number of balls floating indicates condition of battery. If any cell reads two balls or less floating, recharge battery for 10 hours.

TRIMMER SPECIAL TOOLS


SECTION TOOLS SPECIAL ITEMS 14

SERVICE BULLETIN REFERENCES 14-1 1

14-12

COMPLIANT MOWER SERVICE TOOLS

PART NO. 683055

611592 CLUTCH REMOVAL TOOL USED TO RETAIN BRAKE CLUTCH ASSEMBLY.

683242 CLUTCH PULLER USED TO PULL BRAKE CLUTCH ASSEMBLY.

REVISED 1983 SERVICE BULLETIN REFERENCES

COMPLIANT’ M O W E R S E R V I C E TOOLS

611918 SEAL PROTECTOR USEd TO PROTECT SEALS DURING INSTALLATION

611591 MOUNTING PLATE LOCATOR USED TO ALIGN ENGINE ON MOUNTING PLATE

61 1703 USED TO ADJUST CONTROL CABLE CONTROL CABLE GAUGE


COMPLIANT MOWER SERVICE TOOLS

611702 BRAKE SWITCH ADJUSTING GAUGE USED! TO ADJUST BRAKE SWITCH 3-JAW PULLER AVAILABLE FROM

OWATONNA TOOL CO., OWATONNA MN.

OTC NO. STD-80

Used to remove bearing, ramp and arm assembly Used to remove clutch plate from crankshaft if from crankshaft. “BBC” assembly separates. 14-14 REVISED 1983 SERVICE BULLETIN REFERENCES

SERVICE SHOP AIDS SECTION 14

384884

Ultra Lok is an adhesive used on all fastener the deck.

's under

38851 7

! 390928

SAFETY WARNING

Will burn if it comes into contact with skin.


378642

609790 50 cc’s

610377 6 cc’s LAWN-BOY OIL TEST CARDS

Easy to use when demonstrating to customer the proper fuel/lubricant mixture. Occasionally it is necessary to provide visual evi- dence that an insufficient amount of lubricant was mixed in the fuel. Using this card will help to determine if the mixture was or was not correct. TEST PROCEDURES: Determine what kind of oil and gas the customer was using. I t then becomes necessary to correctly mix the same kind of oil and gas in the recommended ratio. (32:l or 16:l) 14-16 REVISED

Place a sample of the customer’s mixture in #2 circle and a sample of the correct mixture in #3 circle. Place a sample of straight gasoline in #1 circle. Gasoline evaporates very quickly. When gasoline in #1 has evaporated, it will also have evaporated from #2 and #3. The circle with the darkest appearance will have more oil than the other. This test should be made in the presence of the customer to eliminate doubts of the results. Use as an aid for selling Lawn-Boy Lubricant.

1983 SERVICE BULLETIN REFERENCES

LAWN-BOY MOWER MONITOR


A digital voltmeter is recommended for use in checking battery voltage also to determine the battery charger output.

Open circuit voltage (O.C.V.) of all batteries r e ceived on warranty claims will be checked. If they register .O volts or more when received and can be recharged, the warranty claim will be rejected and returned with the battery. If possible, battery should be placed on an electric start mower and checked for cranking ability.

Before returning a battery to the factory with a warranty claim because it "won't hold or take a charge," or "will not crank the engine," please refer to Section 13, page 18 of the Lawn-Boy Service Manual for the testing procedures.

Step 1 Check battery voltage with a volt meter before charging.

Step 2 -If the meter indicates an open circuit voltage (O.C.V.) of 11 .O volts or more, connect it to the Lawn-Boy charger for a period of 24 to 48 hours.

Step 3 Disconnect charger and let battery set for a minimum of 24 hours.

If battery voltage is 12.3 volts or higher after completion of this procedure, it should be returned to the customer for continued use. If possible, place it on an electric start mower and check for cranking ability.

If possible, the customer's battery charger should be checked. It should produce between 8 and 12 volts on a volt meter.

The Digital Multi Meter illustrated is available from the Lawn-Boy Service Department. It will check AC and DC voltage, AC and DC current, resistance, check diodes, amperes and continuity.

S.L.A. BATTERY

MODEL 8050 SOAR DIGITAL MULTI METER

14.1 8 REVISED 1983 SERVICE BULLETIN REFERENCES

SECTION 16 QUICK REFERENCE CHART,

ENGINE .AND TORQUE SPECS

u W



SERVICE BU

LLETIN REFERENCES

16-3

e e

E:

E W a

X


E

I

E E W *

16-6 SERVICE B

ULLETIN

REFERENCES

m

I-

x

c


I I


I

SERVICE BU

LLETIN REFERENCES

16-9

I x

16-10 SER

VICE B

ULLETIN

REFERENCES

E d x W E

W

SERVICE BU

LLETIN REFERENCES

16-11

Revised 1977 SERVICE B

ULLETIN

REFERENCES


Revised



w m

16-16 REVISED 1984


NO

SERVIC

E BULLETIN REFER

ENC

ES.. REVISED

Ob

W

w

16-18 REVISED 1984

.SERVIC

E BULLETIN REFERENCES

SERVICE BULLETIN REFER

ENC

ES.. .1&19

REVISED

16-20. .SER

VICE B

ULLETIN

REFER

ENC

ES REVISED 1983

x

SERVIC

E BULLETIN REFER

ENC

ES.. .16-21

REVISED 1983

T O R Q U E REFERENCE

STANDARD TORQUE REQUIREMENTS UNLESS LISTED SPECIFICALLY

THREAD SIZE

10-32 1/4-20

5/16-24 3/8-16 3/8-24

5/16-18

TORQUE INCH POUNDS

35-38 63-75 142-170 142-170

235-280 190-225

"D"

X

X

X X X X X X

X X X

X X X X X X

X X X X

X

X

X

DESCRIPTION

NUT, Flywheel NUT, Flywheel SCREW, Shroud to armature

plate (1964) SPARK PLUG SCREW, Flywheel ring TANK TO SHROUD (1964)

*SCREW, Armature plate to crankcase SCREW, Dust cover BOLT, Shoulder, variable speed

SCREW, Lamination mounting SCREW, Starter attachment SCREW, Condenser mounting SCREW, Condenser mounting SCREW, Breaker base SCREW, Shut off switch SCREW, Starter pully NUT, Condenser SCREW, Cylinder to crankcase SCREW, Reed plate to

NUT, Reed plate to carburetor SCREW, Reed plate to crankcase SCREW, Filter cup to carburetor SCREW, Throttle shaft disc SCREW, Choke and throttle disc NOZZLE

NOZZLE

SCREW, Float chamber SCREW, Star t cap to base SCREW, Starter to shroud NUT, S tar te r to shroud SCREW, Connecting rod SCREW, Tank strap

lever

carburetor

TYPE: 1. NUT, Nylok 2. NUT, Conelok 3. NUT, Standard 4. SCREW, for nylok nut

-.---.-I___ CHECK THE MOWER BEFORE USE Check all nuts, bolts and fasteners for tightness, especially

spark plug lead before check. the blade nut (torque blade nut to ft. lbs.). Disconnect



Check grass or leaf bags for wear or deterioration. Replace bag if necessary.

Gasoline is extremely flammable and highly explosive under certain conditions. Always stop engine, and do not smoke or allow open flames or spark when mixing fuel or refueling.

HANDLE FUEL PROPERLY

ENGINE HARDWARE TORQUE -

'APPLY 682301-NUT &SCREW LOCK ADHESIVE. 16-22.. .SERVICE BULLETIN REFERENCES

REVISED 1983

J E'

SIZE _I-..

7/16-2( 7/16-2( 1/4-20

14 10-24 1/4 20 1/4-20 10-24 10-24

10-24 1/4-20 10-24 10'-24 10-24 a-'1 8 8-32 6-32 5/16-11 1/4-28

1/4-28 1/4-20 5-32 2-56

#2 172

BRASS #72

BRASS 6-32 10-24 1/4-20 1/4-20 12-24

#10 -.I-

-__

PART NUMBER

604273 130981 602848

ALL 309072 132823 306408 604344 604280

510195 602192 510193 602651 302812 602625 602821 133079 602657 132492

602 20 1 602192 602775 604205 53x220 604282

601096

604336 304381 602840 603477 603976 602012

ASSEMBLY TORQUE NCH POUNDS

375/400 375/400

60/75

150/180 20/ 2 5 63/75 63/75 20/ 2 5 20/ 2 5

20/ 2 5 58/63 20/ 2 5 20/25 20/25

16/19 10/13

105/115 63/75

6/8

63/75 16/19

5/7 3/5

16/19

16/19

12/15 20/ 2 5 63/75

55/65 15/30

5. SCREW, Standard machine 6. SCREW, Thread cutting 7. THREAD, Die cas t 8. JOINT, Gasketed

RECHECK TORQUE INCH POUNDS

3 20 180

144 20 60 60 20

20 50 20 20 20 6

15 10 90 60

60 15

5

15

15

10 20 60

55

REFERENCE

CREW, Governor lever CREW, Filter up on C-74 CREW, Air filter C-74 CREW, Filter cup C-72 CREW, Chamber intake

SCREW, Scraper bracket

NUT, Scraper bracket to 1/4-20 603477 shroud C 72

Shut off switch

DESCRIPTION

SCREW, Handle bracket SCREW, Handle SCREW, Muffler plate SCREW, Engine mounting

~~~ __-___ TYPE: 1. NUT, Nylok 5. SCREW, Standard machine

2. NUT, Conelok 6. SCREW, Thread cutting 3. NUT, Standard 7. THREAD, Die cast 4. SCREW, for nylok nut 8 . JOINT, Gasketed

SERVICE BULLETIN REFERENCES.. .16-23 REVISED 1983

TORQUE, REFERENCE

19"

DESCRIPTION TYPE

SCREW, Handle bracket (Model 5233) SCREW, Handle bracket (Model 52303) SCREW, Handle SCREW, Muffler to muffler plate BOLT, Wheel lever (Model 5233) SCREW, Muffler plate to housing SCREW, Crankcase to muffler plate (Model 5233) NUT, Blade BOLT, Shoulder, wheel SCREW, Wing, cover chute (Model 5233)

21" Deluxe

DESCRIPTION

SCREW, Handle bracket SCREW, Handle SCREW, Wing, cover chute opening to housing SCREW, Wing, grass chute to housing (Models

SCREW, Wing, grass chute to housing (Models

SCREW, Speed nut to housing NUT, Grass chute NUT, Blade BOLT, Shoulder, wheel BOLT, Wheel lever SCREW, Muffler to muffler plate SCREW, Muffler plate to housing SCREW, Crankcase to muffler plate NUT, Mounting bracket screw SCREW, Mounting bracket

7254 and 7254WB)

7254 and 7254WB)


I ASSEMBLY RECHECK SIZE

1/4-20 5/16-18 1/4-28 1/4-20 5/16-18 5/16-18 5/16-18 5/8-18 3/8-16 1/4-20

TORQUE

60/75 135/165 60/75 58/63 135/165 142/170 142/170 525/650 200/240 20/30

INCH POUNDS TORQUE INCH POUNDS

50

135 135

SIZE

1/4-20 1/4-28 1/4-20

1/4-20

1 /4-20 1/4-20 8-32 5/8-18 3/8-16 5/16-18 1/4-20 5/16-18 5/16-18 1/4-28 1/4-28

ASSEMBLY TORQUE INCH POUNDS

60/75 60/75 20/30

30/40

30/40 30/40 15/20 525/650 200/240 135/165 58/63 142/170 142/170 63/75


50 135 135 60

5. SCREW, Standard machine 6. SCREW, Thread cutting 7. THREAD, Die cast 8. JOINT, Gasketed

SELF-PROPELLED (GEAR DRIVE) PART NO. ASSEMBLY TORQUE

SCREW, Transmission to housing Aluminum bracket to bearing ass'y. 306832 63/75

SCREW, Transmission to housing plastic bottom gear cover 608291 30140

\

16-24.. .SERVICE BULLETIN REFERENCES REVISED 1983

TORQUE REFERENCE

Commercial

DESCRIPTION

SCREW, Handle bracket SCREW, Handle SCREW, Muffler to muffler plate BOLT, Wheel lever SCREW, Muffler plate to housing SCREW, Crankcase to muffler plate SCREW, Fuel tank bracket to housing SCREW, Fuel tank strap BOLT, Shoulder, wheel SCREW, Wing, cover chute SCREW, Housing NUT, Blade NUT, Name plate, thread cutting

TYPE

4 4 598 4 4 4 4 5 795 6 6 1,8

SIZE

1/4-20 1/4-28 1/4-20 5/16-18 5/16-18

1/4-20 10-24 3/8- 16 1/4-20 10-32 5/8-18

5/16-18

ASSEMBLY TORQUE

60/75 60/75 58/63 135/165 142/170 142/170 63/75 16/19 200/240 20/30 25/40 525/650

INCH POUNDS


50

135 135 60 15

SAFETY WARNING SAFETY WARNING

when replacement parts are required, use Apply OMC No. 388517 ULTRA-LOC to all genuine OMC parts or parts with equiva- fasteners within the cutting chamber and lent characteristics including type, MUST be tightened to specified torque to strength, and material. Failure to do so avoid coming loose, thus becoming a thrown may result in product malfunction and object if hit by the blade. possible injury to the operator and/or passengers.

SERVICE BULLETIN REFERENCES.. .16-25 REVISED 1983

TORQUE REFERENCE

MODEL 9213 HARDWARE TORQUE

DESCRIPTION

NUT, Handle bolt NUT, Bracket to handle pivot clamp screw NUT, Bracket to tongue screw NUT, Pin weld head pivot NUT, Foot pedal screw NUT, Mower mounting plate screw NUT, Eye bolt NUT, Wheel, bolt, right NUT, Wheel, left SCREW, Guard to housing NUT, Brace bar screw NUT, Shroud to draw bar brace screw SCREW, Cap disc NUT, Shroud frame to transmission plate screw NUT, Seat support to shroud frame screw SCREW, Oil filler bracket NUT, Seat to cover bolt SCREW, Shroud to cover NUT, Arm, clutch to brace, clutch arm screw NUT, Clutch arm to engine mounting plate screw NUT, Clutch adjusting screw SCREW, Engine mounting plate to armature plate SCREW, Bearing engine mounting to engine

NUT, Bell crank bolt NUT, Engine mounting screw NUT, Muffler clamp to cylinder screw SCREW, Muffler clamp to cylinder NUT, Muffler clamp screw NUT, Muffler cover to muffler screw SCREW, Roller SCREW, Set drive shaft SCREW, Pinion gear pin SCREW, Transmission plug SCREW, Plug, oil drain

mounting plate

SCREW, Axle collar SCREW, Differential lockplate


I

TYPE

1 1 1 1 1 1 3 1 1 597 1 1 5,7 1 398 6 3 6 1 1 3 6

6 1 1 2 5 2 3,8 6,7,8 5,7 5,7 597 7

5,7 597

SIZE,

1/4-28 5/16-18 1/4-28 5/16-18 5/15-18 1/4-28 3/8-16 5/16-24 9/16-18 5/16-18 5/16-18 5/16-18 3/8-24 5/16-18 5/16-18 #10 1/2-13 5/16-18 1/4-28 5/16-18 3/8-16 5/16-18

#10 5/16-18 5/16-18 1/4-20 1/4-20 5/16-18 1/4-20 1/4-20 5/16-18 5/16-18 1/4-20 1/8-27 N.P.T.F 5/16-24 5/16-24

ASSEMBLY TORQUE

63/75 142/170 63/75 142/170 142/170 63/75 225/190 142/170 450/550 142/170 142/170 142/170 225/275 142/170 142/170 30/50 250/350 142/170 63/75 142/170 200/240 142/170

15/20 142/170 142/170 63/75 63/75 142/170 63/75 63/75 80/100 142/170 63/75

INCH POUNDS

120/150 120/150

RECHECK TORQUE

60 135 60 135 135 60 180 135

135 135 135

135 135

INCH POUNDS

135 60 135

135

135 135 60 60 135 60 60

135 60

5. SCREW, Standard machine 6. SCREW, Thread cutting 7. THREAD, Die cas t 8. JOINT, Gasketed


TORQUE REFERENCE

HARDWARE TORQUE

MODEL 9213 (Continued)

ASSEMBLY RECHECK DESCRIPTION TYPE SIZE INCH POUNDS INCH TORQUE POUNDS

TORQUE

NUT, Draw bar screw 1 5/16-18 142/170 135

MODEL Automower

DESCRIPTION

NUT, Handle screw SCREW, Handle bracket NUT, Handle bar sc rew SCREW, Set, roller driveshaft SCREW, Wing, grass chute shaft to housing SCREW, Wing, grass chute to housing SCREW, Speed nut to housing SCREW, Wing, cover, chute opening to housing SCREW, Grass chute BOLT, Wheel lever BOLT, Shoulder wheel NUT, Blade SCREW, Sub base mounting SCREW, Crankcase to sub base NUT, Muffler to muffler plate SCREW, Muffler plate to housing BOLT, Shoulder SCREW, Driveshaft bracket


SIZE

1/4-28 1/4-20 10-24 3/8-24 1/4-20 1/4-20 1/4-20 1/4-20 8-32 5/16-18 3/8-16 5/8-18 5/16-18 5/16-18 1/4-20 5/16-18 1/4-28 1/4-28

ASSEMBLY TORQUE

63/75 63/75 20/25 130/160 30/40 30/40 30/40 20/30

142/170 200/240 525/650 142/170 142/170 63/75 142/170 63/75 63/75

INCH POUNDS

RECHECK TORQUE

60 60 20

INCH POUNDS

135

135 135 60

135 60 60

5. SCREW, Standard machine 6. SCREW, Thread cutting 7. THREAD, Die cast 8. JOINT, Gasketed



THREAD SIZE

TORQUE INCH POUNDS

10-13 4-40 5-7 6-32 8-18 16-19 8-32 10-16 25-30

16-19

10-24 20-25 10-32 12-24

35-38 58-70

1/4-20 63-75

5/16-24 5/16-18 142-170

3/8-16 142-170 190-225

3/8-24 235-280

CHECK THE MOWER BEFORE USE Check all nuts, bolts and fasteners for tightness, especially the blade nut (torque blade but to 50 ft. lbs.). Disconnect spark plug lead before check to prevent accidental restarting of mower.




HANDLE FUEL PROPERLY

conditions. Always stop engine, and do not smoke or allow open flames Gasoline is extremely flammable and highly explosive under certain

or spark when mixing fuel or refueling.

SERIES “F” EXCLUDING 1983 & LATER BBC MODELS

DESCRIPTION

Nut Flywheel Seat Float Valve

Screw Ignition Bracket to Cyliner Screw Crankcase tu Cyliner Screw Shroud Base to Cyliner Assembly

Screw Set Starter to Crankcase Cover

**Screw Reed to Crankcase Cover

*Nut Blade

Bolt Wheel Nut Shoulder Bolt Wheel Bracket Screw Connecting Rod Cap

Screw Axle Cover Mounting Screw Flywheel Screen

*Screw Muffler Plate to Housing

*Screw Handle Bracket to Housing **Screw Ignition Pack (C.D.) to Bracket

Screw Cylinder to Muffler Plate Spark Plug

Screw Roller Guard Mounting Screw Plate and Chute Mounting

*Nut Muffler Plate to Housing Screw Float Bowl to Carburetor Body Screw Baffle to Shroud Base Screw Engine Shroud to Base Screw Gearbox to Crankcase Cover

Screw Carburetor to Crankcase Screw Switch Box to Shroud Bolt Shoulder Lockout Lever to Crankcase Bolt & Nut Height to Housing Adjustment Screw Transmission to Housing Aluminum Screw Transmission to Housing (Plastic Cover)

*Screw Muffler to Muffler Plate *Nozzle Carburetor

*Screw Crankcase Support and Muffler Cover to Muffler

**Screw Alternator to Bracket

Plate

SAFETY WARNING

When replacement parts are required, use genuine OMC parts or parts with equivalent characteristics including type, strength, and material. Failure to do so may result in product malfunction and possible injury to the operator and/or passengers.

*Apply OMC Part #388517 ULTRA-LOC (Loctite #271) **Apply 384848 Screw-Loc.

ASSEMBLY

INCH TORQUE

MAX.

400 23 13 75

115 75

650

225 95

225

170 65

30 25

170 25

180

170 190

35 170

13 13

40 13

170 30 13 75 75 70 40

190

25 12

RECHECK

INCH POUNDS TORQUE

375 19 10 63

105 63

525 85

190 190

142 55

20 25

142 20

150 150 142 30

142 10 10

30 10

142 25

63 10

63 60 30

150 8

20

320 18

60 10

90 60

500 80

180 180

135 20 20

135 20

144 135 135 30

135

10 6

30 10

135 25

60 10

60 63 30

I 135 10 20

SAFETY WARNING

Apply OMC No. 388517 ULTRA-LOC to all fasteners within the cutting chamber and MUST be tightened to specified torque to avoid: coming loose. thus becoming a thrown object if hit by the blade.


TORQUE SAFETY WARNING REFERENCE


THREAD SIZE

4-40 6-32 8-18 8-32 10-16 10-24 10-32 12-24 1/4-20 5/16-18 5/16-24 3/8-16 3/8-24

INCH POUNDS TORQUE

10-13 5-7

16-19

25-30 16-19

35-38 20-25

63-75 58-70

142-170 142-170

235-280 190-225

CHECK THE MOWER BEFORE USE Check all nuts, bolts and fasteners for tightness, especially the blade nut (torque blade nut to 50 ft. lbs.). Disconnect spark plug lead before check to prevent accidental restarting of mower.




HANDLE FUEL PROPERLY Gasoline is extremely flammable and highly explosive under certain conditions. Always stop engine, and do not smoke or allow open flames or spark when mixing fuel or refueling.

SERIES “F” COMPLIANT MOWERS (BBC)

DESCRIPTION

Nut Flywheel Zinc Seat Float Valve

**Screw Reed to Crankcase Cover Screw Ignition Bracket to Cyliner Screw Crankcase to Cyliner Screw Shroud Base to Cyliner Assembly

*Bolt Blade (2) *Screw Clutch Brake Retaining *Nozzle Carburetor

Screw Spring Box Mounting Bolt Shoulder Brake Cable Clevis Screw Set Starter to Crankcase Cover

Nut Shoulder Bolt Wheel Bracket Screw Connecting Rod Cap

Screw Axle Cover Mounting Screw Flywheel Screen

Bolt Wheel

*Screw Muffier Plate to Housing

*Screw Handle Bracket to Housing **Screw Ignition Pack (C.D.) to Bracket

Screw Cylinder to Muffler Plate Spark Plug

Screw Roller Guard Mounting Screw Plate and Chute Mounting

*Nut Muffler Plate to Housing Screw Float Bowl to Carburetor Body Screw Baffle to Shroud Base Screw Engine Shroud to Base Screw Gearbox to Crankcase Cover

Screw Carburetor to Crankcase Screw Switch Box to Shroud Bolt Shoulder Lockout Lever to Crankcase Bolt & Nut Height to Housing Adjustment

*Screw Transmission to Housing Aluminum *Screw Transmission to Housing (Plastic Cover)

Screw Crankcase Support and Muffler Cover to Muffler Plate

**Screw Alternator to Bracket

SAFETY WARNING

When replacement parts are required, use genuine OMC parts or parts with equivalent characteristics including type, strength, and material. Failure to do so may result in product malfunction and possible injury to the operator and/or passengers.

ASSEMBLY TORQUE

INCH-j MAX.

400 23 13 75 115 75 380 375

170 12

75 95 225 225

170 65

30 25 170 25 180 190 170 35 170 13 13 13

170 40

30

75 13

75 70 40 25

BLY TORQUE POUNDS

MIN.

375 19 10 63 105 63 340 275

142 8

63 85 190 190

142 55

25 20 142 20 150

142 150

30 142 10 10 10

142 30

25

63 10

63 60 30 20.

RECHECK TORQUE

INCH POUNDS

320 18 10 60 90 60 320 250

135 10

60 80 180 180

135 20 20 135 20 144

135 135

30 135

10 6

10

135 30

25

60 10

60 63 30 20.

SAFETY WARNING

Apply OMC No. 388517 ULTRA-LOC to all fasteners within the cutting chamber and MUST be tightened to specified

object if hit by the blade. torque to avoid coming loose, thus becoming a thrown

*Apply OMC Part 1388517 ULTRA-LOC (Loctite #271). **Apply 384848 Screw-Loc.


MODELS

Horse Power Bore Stroke Displacement Cu. In. Displacement CC’s

CRANKSHAFT Top Journal Both Lower Push Lower Self-Propelled Crank Pin Wrist Pin Diameter End Play (Crankshaft) Side Play (Crankshaft) Next to Seals PISTON Diameter (Right Angle Wrist Pin Hole) (Bottom of Skirt) Diameter (Parallel Wrist Pin Hole) (Bottom of Skirt) Diameter Wrist Pin Hole Compression Ratio Compression Min. (Cold) Compression (Normal) Cold Compression (Normal) Hot

PISTON RINGS Thickness Top Thickness Bottom End Gap (In Cylinder) Top End Gap (In Cylinder) Bottom

CYLINDER Diameter (Inside)

BREAKER POINT GAP Coil Air Gap C.D. Module Air Gap Alternator Air Gap SPARK PLUG GAP Type Spark Plug Champion Type Spark Plug A-C Type Spark Plug Autolite Governor Speed High Governor Speed Low

3-1/2+ H.P. 2.3810-2.3800 1.7502-1.7497 7.78 127.51

8778-8773 8778-8773 1.1270-1.1265 7430-7425 .5000-4998 .006-.016 .0065 max.

2.377-2.376 2.369-2.3725 .5005-5001

80 PSI 5.89:l

100-115 PSI 90-105 PSI

0690-0700 .0615.0625 .007-.017 .015-.025

2.3810-2.3800

.010

.010 .035 CJ-14 c s 4 9 A-11X 3100-3300 RPM 2400-2600 RPM

“D-600” SERIES

3-1/2 H.P. 2.3750 1.500 6.65 108.99

.8742-.8737. 8742-8737

7430-7425 .5000-.4998 .007-.017. .0065 max.

2.3759-2.3749 2.3714-2.3679 .5005-.5000 5.5:l 70 PSI 90-105 P S I 80-95 PSI

.0615-.0625

.0615-.0625

.015.025 ,015.025

2.3800-2.3810

.010 ,010 .035 CJ-14 c s 4 9 A-11X 3100-3300 RPM 2400-2600 RPM

“D-400” SERIES

3-1/2 H.P. 2.3750 1.500 6.65 108.99

8742-8737 8742-8737

7430-7425 .5000-.4998 .007-.017. ,0065 max.

2.3759-2.3749 2.3714-2.3679 .5005-.5000 4.5:1 65 PSI 70-85 PSI 60-80 P S I

.0615-0625

.0615.0625

.015-.025

.015-.025

2.3800-2.3810

.020

.010

.025 CJ-14 cs-49 A-11X 3100-3300 RPM 2400-2600 RPM


ENGINE

Horsepower Bore Stroke Displacement Piston Diameter Breaker Point Setting Coil A i r Gap

C/D Air Gap Spark Plug

GOVERNED SPEED Fuel Mixture

A-10, A-11, A-13

1-3/4 in. 1-1/2 in. 3.603 cu. in. 1.7470-1.7465 .020 .010

Champion CJ-14 o r equivalent. Gap-.025

REFER TO SECTION 1 can Lawn-Boy Lubricant per 1 gal regular gasoline

See Owner-Operato Manual for complete instructions

c-10, c-12, c-20, C-21, C-22, C-70. C-71, C-72, C-73, c-75

1-15/16 in. 1-1/2 in. 4.43 cu. in. 1.9360-1.9355 .o20 .010+

Champion CJ-l4 o r equivalent. Gap-.025

(ENGINE QUICK 1 can Lawn-Boy Lubricant per 1 gal. regular gasoline See Owner- Operator Manual for complete instructions

2.5 (3 H.P.) 2-1/8 in. 1-1/2 in. 5.22 cu. in. 2.1205-2.1200 .020 .010

Champion CJ- o r equivalent. Gap-.025

C-13 thru C-17 C-18, C-19, C-19B C-40 thru C-42 C-43, C-44 C-50, C-51, C-60, D-400 thru D-408, C-61, C-80, C-8i, D-405E thru D-408E,

C-78 D-440 thru D-448 C-74, C-76 thru D-430, D-431,

D-445E thru D-448E D-450 thru D-452 D-460 thru D-462 D-475 D-480 D-600

3-1/2 2-3/8 in. 1-1/2 in. 6.65 cu. in. 2.3720-2.3715 .o20 678103 Flywheel .016 .010 .010

.14 Champion CJ-14

D-400 Series-.025 D-600 Series-.O35

o r equivalent.

REFRENCE CHART) FOR RECOMMENDED

gal. regular Lubricant per 2 gal . gasoline regular gasoline See Owner-

instructions Lubricant per 1 gal. regular gasoline See Owner-Operator Manual for complete instructions

D D D D D

6

1954-77 MODELS

D-409, D-433 D-449, D-463 D-476. D-481 D-601, D-601E D-640, D-641 D-641AE

3-1/2 2-3/8 in. 1-1/2 in. 6.65 cu. in.

.020

.010

.010 Champion CJ-14 or equivalent.

D-400 Series-.O25 D-600 Series-.03 SPEEDS 1 can Lawn-Boy Lubricant per 2 gal. regular gasoline

CLEARANCES CRANKSHAFT Top Journal Crank Pin

Bottom Journal Bottom Journal

Wrist Pin Hole Crank Pin Hole

CONNECTING ROD

WRIST PIN

PISTON Diameter (skirt)

Diameter Wrist Pin Hole

Diameter End Gap (In Cyl.)

CYLINDER Thickness

Inside Diameter Sub-Base Bushing

Sub-Base Bushing

Top Bearing Bottom Bearing

Bearing

PISTON RINGS

SUB-BASE HOUSING

CRANKCASE

ARMATURE PLATE

.6692-.6689

.6865-.6860

.6692-.6689

.3659-.3654

.6880-.6875

.3650-.3642

1.7470-1.7465 .3655-.3650

1.740 ± .OOO .020 ± .005 ,0935-.0930

1.751-1.750 .683-.680

.683-.680

.4275-.4280

.7530-.7525 '".9427-.9422

.4272-.4270

1.9360-1.9355 .4275-.4272

1.9375 ± .OOO .020 ± .005 ,093 ± .0005

1.940-1.941

*C-16, C-17, and C-42. C-51, C-61, C-81 engines **C-73 engine

++c-18 c -19 , C-19B, C-43, C-44, D-400, D-401 engines +C-71 engine

.8742-.8737 .7430-.7425 .7500-.7495 .8742-.8737

*.7430-.7425 ,8742-.a737 .8742-.8737

.4908-.4903 .9427-.9422 .7531-.7525 .4908-.4903

*.9427-.9422

.4900-.4898 .4900-.4898

x2.1205-2.1200 .4900-.4905 x4900- .4905 2.3720-2.3715

2.125 ± .OOO .005-.015 .020 ± .005 2.378-2.377

.098-.088 .0615-.0625

xx2.126-2.125 xx2.378-2.377

.8770-.8762 .8805-.8780 .8805-.8780

tt.8770-.8762

.8770-.8762 .8762-.8746

.8742-.8737

.7430-.7425

.8742-.8737 X1.1250-1.1245

.9427-.9422

.5000-.4998

2.3759-2.3749 .5005-.5000

2.378-2.377 .005-.015 .0615-.0625

2.3800-2.3810

.8805-.8780

I I

xModel C-77 2,188 piston diameter #Models D-481, .4900-.4905 wrist pin hole; D-640 and Model C-78 2,438 piston diameter .4900-.4905 wrist pin hole.

D-641 only

xx1967 "D" series and model C-78 2.380-2.381 cylinder diameter.



ENGINE TEAR D O W N

Engine tear down and assembly is easy if done right. Use the right tools, disassemble in correct order, and remove complete assemblies intact where possible. Proceed as follows:

“C” SERIES A T U R N FUEL VALVE OFF AND DISCON- NECT GAS LINE FROM CARBURETOR, REMOVE CHOKE ROD FROM CHOKE SHAFT, AND REMOVE COMPLETE ENGINE SHROUD, GAS TANK AND RECOIL STARTER AS AN ASSEMBLY.

SPARK PLUG AND INSTALL PISTON STOP PART NO. 677389. REMOVE FLYWHEEL NUT AND WASHER.

LIFT STARTER PULLEY, PLATE, SCREEN PIN AND SPRING OFF FLY-

WHEEL.

REMOVE FLYWHEEL. PLACE NUT CRANKSHAFT NEARLY FLUSH WITH TOP CRANKSHAFT. LIFT U P ON FLYWHEEL,

ON

TAP OF SHARPLY ON THE NUT WITH A SOFT HAMMER. THE FLYWHEEL SHOULD SNAP LOOSE EASILY. REMOVE FLYWHEEL KEY WITH PAIR OF SIDE CUTTERS OR DIKES.

@CAREFULLY LIFT GOVERNOR YOKE, FLYWEIGHTS AND COLLAR OFF AS AN ASSEMBLY. SET ASIDE CAREFULLY.

GOVERNOR SPRING.


ENGINE TEAR DOWN

“C” SERIES REMOVE GOVERNOR LEVER AND WEAR

BLOCK ASSEMBLY. EXAMINE WEAR BLOCK. IF WORN ON ONE SIDE TURN

PLACE. OVER. IF BOTH SIDES ARE WORN RE-

COMPLETE MAGNETO PLATE BY RELEASING THREE SCREWS.

NOTE APPLY THREE OR FOUR DROPS OF 20 OR 30 WT OIL TO OILER

NOTE

CONNECTING ROD BEARING IN- CLUDES 33 LOOSE NEEDLES. EX- AMINE FOR WEAR. .RE-INSTALL BY USING HEAVY GREASE. PLACE 17 NEEDLES ON ROD CAP AND 16 ON ROD. VERY EARLY MODEL ENGINES WILL NOT HAVE NEEDLE BEARINGS.

AND REED PLATE ASSEMBLY. CONNECTING ROD CAP

SCREWS. USE CORRECT SIZE SCREW DRIVER.

REMOVE CYLINDER HEAD BOLTS AND GASKET.


TEAR DOWN “C” SERIES

REMOVE PISTON, ROD AND RING AS- SEMBLY FROM CYLINDER. NOTE: Pull the piston and connecting rod assembly out quickly or the rings may bind or break.

REMOVE THE CRANKSHAFT FROM THE CRANKCASE THROUGH THE TOP.

EARLY MODELS

LATER MODELS

THE ENGINE IS NOW COMPLETELY DISASSEMBLED INTO ITS MAJOR PARTS.


REASSEMBLY .TIPS “ C ” MODEL ENGINES

CHECK INTAKE PORTS ON NEW CYLINDER FOR BURRS AVOID SCORES.

I CORRECTLY ALIGN CYL- INDER AND REED PLATE GASKETS MUST NOT BLOCK OIL PASSAGES.

INSERT CRANKSHAFT CAREFULLY THROUGH OIL SEALS TOP AND BOTTOM AVOID SEAL

\ CHECK OIL PASSAGES OIL CONNECTING ROD MUST BE CLEAR FREE AND THE CRANKSHAFT

DAMAGE.

OF DIRT.

POSITION KEYWAY AND KEY EXACTLY BEFORE

USE ALL NEW GASKETS.

INSTALLING FLYWHEEL.

TIGHTEN SCREWS, NUTS AND BOLTS refer to torque chart, SECTION 16.

CHECK GOVERNOR FOR CORRECT ENGINE

QUIRED AFTER ASSEMBLY COMPLETED. RECOMMENDED ENGINE SPEED IS 3100-

IF ENGINE RUNS ABOVE 3300 R.P.M. THE BLADE TIP SPEED WILL EXCEED THE FEDERAL SAFETY STANDARDS OF 19O00 FT. PER MINUTE. ON DRY TYPE AIR FILTER EQUIPPED ENGINES, REPLACE FILTER ELEMENT ON ENGINE OVERHAUL.

R.P.M. ADJUSTMENT TAKES TIME IF RE-

3300 R.P.M.


R E P A I R I N G E N G I N E S WITH N E E D L E B E A R I N G C O N -

N E C T I N G R O D A S S E M B L Y t i

NEEDLE BEARING STRIP

BEARING R

Lay bearing strip on forefinger. Care- fully peel off backing. Curl finger around crankpin so needles transfer and stick to pin.

Always check needle bearings and retainers on engine overhaul. Before removing connecting rod from crankpin, see if needles can be cocked or separated more than diameter of one needle. After removal, look for discoloration from heat, scoring or flat spots on needles. Replace needle bearings and bearing retainers as complete sets only. Needle bearings, pre- coated with grease, are supplied in strips of 33 (one set).

INSTALLATION OF NEEDLE BEARINGS Press bearing retainers into connecting rod and cap. Be sure dove-tail ends of retainer halves match when mating marks on connecting rod and cap match.

NOTE: Check crankcase for needle bearings that may have dropped inside during disassembly-.

f’\

ing rod to cap.

Check crankcase for needles that may have dropped out during assembly. Oil after assembly. loosening of the screws.


GOVERNOR OPERATION

A governor is simply a device which will automatically increase the power output of an engine when an additional load is put on the engine, and decrease the power output when the load is lightened. Different governors are used on the "C" and "D" Series Lawn-Boy engines, though all operate on the same principle. For flywheel removal see page 17-2. Basically, the governor operates through weights which pivot out from the rotating crankshaft. When the engine is under -no load, the crankshaft rotates faster and the centrifugal force swings the weights out.

C SERIES GOVERNOR

Engine speed should be 3200 RPM or 2800 RPM. This difference is accomplished with the spring. In other re- spects the governors are identical. The 2800 RPM spring is color coded (RED); the 3200 RPM spring is un- colored. If spring is distorted, replace. DO NOT ATTEMPT TO ADJUST GOVERNOR BY STRETCHING SPRING.

GOVERNOR ADJUSTMENT

602885 3/16 INCH

GOVERNOR

ROD


Under load, the crankshaft rotates slower, and the weights drop in. The weights move a collar up- o r down on the crankshaft. This collar is linked to the carburetor throttle disc. As the weights drop in, the linkage opens the throttle disc more, causing the engine to pick up speed until it reaches the correct operating RPM's. The action of the governor is continuous. There should be very little noticeable variation in RPM's of the engines, since any slight increase or decrease in RPM's is immediately transmitted to the carburetor.

FREE LENGTH FREE LENGTH 3/4 IN. .015 IN. .765 IN. .015 IN.

GOVERNOR ADJUSTMENT Special' tool part #602885 must be used for checking the governor adjustment on "C" Se- ries engines. With the governor assembly in place slip the gauge onto the crankshaft and hold down firmly. Holding the gauge in place, depress the throttle shaft to the closed throttle position, and raise the governor lever upward with ,light pressure. If the governor is properly adjusted, there should be approximately 1/8 3/16 inch between the top of the governor rod and the bottom of the governor lever. To make any necessary adjustments simply bend (the governor lever is creased diagonally to simplify adjustment bend lever along crease) the governor lever up o r down with a pair of pliers to obtain the proper clearance.

17-7

GOVERNOR SERVICING Normally, little trouble is experienced with governors. Often engine surging is blamed on the governor when carburetion is at fault, If the governor is suspected, check the following:

BINDING OF YOKE, WEIGHTS, OR COL- LAR, Check for burrs or distortion, or binding of a rm at screws.

EXCESSIVE WEAR ON WEAR BLOCK. This can be caused by surging, or rough collar surface. A rough collar can be honed smooth. Apply a light film of grease after honing. If the block is worn just from long usage, it can usually be inverted on the lever.

BINDING OF ROD AT CARBURETOR MOUNTING SCREW, MAGNETO PLATE, OR THROTTLE SHAFT LEAF. Check for burrs. There should be no washer under the reed plate mounting screw nearest governor rod.

CARBURETOR THROTTLE DISC BIND- ING IN CARBURETOR THROAT. This is not a governor malfunction, but may give the same symptoms, such as surging. See Carburetor Section.

GOVERNOR REASSEMBLY

Reassembly of the governor is easier if the In assembly be sure to push the coil wire spring is placed on the crankshaft, and the down below and away from the arc of the yoke, weights and collar assembled sepa- weights. .Otherwise the movement of the rately. Grasp the assembly by the wide weights could wear through the insulation on sections of the weights and slip over crank- the wire. shaft and spring.


STARTER

PRINCIPLE OF STARTER OPERATION

The recoil starter does away with winding a rope around a pulley to start the engine. It consists of a handle attached to a rope, wound around a pulley, and a rewind spring to recoil the rope. A spring loaded pin attached to flywheel engages with starter pulley to turn flywheel and start engine. As soon as the engine starts, centrifugal force moves the pin outward, disengaging it from the starter pulley.

C-12 A N D LATER TYPE

EXPLODED VIEW

The C-12 and later type starter has a larger, two piece pulley. The rope is "locked" in the handle and at the pulley by PRESSING into place. No clamps are required.

ROPE ANCHOR AT PULLEY

ROPE A N C H O R AT HANDLE


STARTER A N D S H R O U D

There were two methods of attaching the rope to the pulley; a bead stop and a rope clamp. The rope clamp was an improvement over the bead clamp.

BEAD STOP FIRST

METHOD

ROPE CLAMP SECOND METHOD

C-10 STARTER

Do not attempt to use the new clamp on an old pulley (with bead), unless the center section is first ground down 3/64” to relieve binding. STARTER ROPE

A new spring was also used, with a different method of anchoring on the starter housing. This spring allowed more flexibility under reverse force if the starter handle was allowed to "snap back."

OLD

'9


Both types are disassembled and assembled in about the same way, except for anchoring the rope. On later models it is necessary to remove the shroud before removing the starter. Remove the three screws as shown and lift starter from base. To remove pulley, take out pulley cap screw.

SAFETY WARNING: WHEN REMOVING P U L L E Y AND SPRING, BE VERY CAREFUL OF SPRING. THE SPRING IS COILED UNDER TENSION IN THE CAP. LEAVE SPRING IN

PLACED. CAP UNLESS IT IS TO BE RE-

DISASSEMBLY AND A S S E M B L Y H I N T S

The rope should be singed a full 3/4 inch at both ends, to be sure it will hold securely.

SERVICE BULLETIN REFERENCES SAFETY RELATED 17-11

DISASSEMBLY AND ASSEMBLY H INTS c-12 To replace spring in starter cap, proceed as follows:

1. With rope anchored and wound in pulley, place inside loop of spring in hub of pulley as illustrated for each type starter.

2. Place pulley on starter cap so that spring runs through slot in cap.

c-10

3. Secure pulley to starter cap with pulley bearing, washer and screw. Tighten screw securely.

4. With a firm grip on the cap, pull rope to 5. Rewind rope on pulley and continue until turn pulley. The turning pulley will draw the spring has been fully drawn in. the spring into the cap.

RIGHT (OUTSIDE RATCHET)

6. With rope fully wound on pulley, turn pulley against spring tension and with rope handle in slot, place starter on base. Hold starter on base and "feel" for proper tension. There must be some tension on spring, otherwise handle will not return all the way to starter when released. NEVER WIND PULLEY OVER TWO TURNS AFTER TEN- SION IS FELT ON SPRING.

7. Replace screws in cap to' base.

WRONG (INSIDE RATCHET')

ON ALL STARTERS, MAKE SURE PIN OR PINS ON FLY- WHEEL PULLEYS ARE ON OUT- SIDE OF STARTER PULLEY RATCHETS, BEFORE TIGHT ENING STARTER TO SHROUD SCREWS.


EDGER-TRIMMER SERVICING

REMOVING ENGINE

REMOVE SPARK PLUG LEAD AND

DENTALLY STARTING ENGINE. SPARK PLUG TO PREVENT ACCI-

Turn spindle head to a vertical position. With Edger backed against a solid surface, push spindle pivot rod against spring to remove belt. Remove three engine mounting screws.

REMOVING SPINDLE PIVOT ROD Slip lock lever spring loop off end of pivot rod. P r y one side of spring off of lock lever roll pin. Drive out pin to release pivot rod.

SPINDLE DISASSEMBLY Remove blade and pulley. Loosen cutter guard clamp lever assembly and remove guard. P res s out spindle shaft and bearings from either end.

SPINDLE AND BEARINGS PRESS OUT FROM

I

CLEANING MUFFLER Remove four muffler screws. Muffler separates completely from axle and muffler plate assembly.

SERVICE BULLETIN REFERENCES Revised 1978 17-1 3

PRE-OPERATION CHECK & FUEL Be sure to read this section carefully before, attempting to operate this unit. 1. Fill fuel tank with oil and gas mixture as indicated on red fuel tag

2. Always make sure gasoline cap is tightened securely before located on trimmer.

attempting to start engine.

READ CAREFULLY LAWN-BOY 2 CYCLE OIL IS RECOMMENDED

FOR THIS LAWN-BOY TRIMMER Fig. 9-Fuel decal located on Lawn-Boy 2 cycle oil is formulated specifically for high performance, two cycle engines. Special additives promote thorough mixing and ready combustion. This give the engine the benefits of clean, fresh, LAWN-BOY 2 CYCLE OIL lubrication every revolution of the crankshaft. MIXING RATIO Thoroughly mix contents of one 8-02. Lawn-Boy 2 cycle oil can with two U.S. gallons of regular grade automotive gasoline. Do not mix di- Lawn-Boy 2 cycle oil regular gas

rectly in engine fuel tank. If you use two-cycle oil other than Lawn- Boy 2 cycle oil, a mixture of 6 oz. oil to 1 gal. gasoline is recommended.

Do not use a synthetic base oil for lubrication in Lawn-Boy Gasoline Trimmers.

trimmer.

NOTE: Remember to pay strict attention to the fuel mixing instructions. DO NOT USE NO-LEAD FUEL OR GASOHOL. NOT FOLLOWING COR- RECT MIXING PROCEDURES CAN CAUSE AN ENGINE TO SEIZE OR OTHER DAMAGE.

Gasoline is extremely flammable and highly explosive under certain conditions. Always stop engine, and do not smoke or allow open flame or spark when refueling.

18-2 SAFETY RELATED REVISED 1983 SERVICE BULLETIN REFERENCES

SERVIC

E BU

LLETIN R

EFEREN

CES

CA

RB

UR

ET

OR

WA

LB

RO

T

ILL

OT

SON

Low

speed m

ixture adj. O

ne 1-1/2 turn from seat

1 turn from Beat

Metering lever

(initially) .060-.070 below carburetor body (m

etering m

etering chamber floor

cover gasket surface Idle speed

2 turns after

contact

Flush with carburetor

with lever

3 turns after contact w

ith lever

18-4 SER

VICE B

ULLETIN

REFER

ENC

ES

TROUBLE SHOOTING POSSIBLE CAUSE AND CHECK POSSIBLE REMEDY

STARTER ROPE WILL NOT REWIND Broken Starter Spring/Not enough Preload

Replace Starter Spring Adjust tension per decal

STARTER DOES NOT ENGAGE FLYWHEEL Broken Pawl Spring Broken Pawls or Pins

Replace flywheel assembly

ENGINE DIFFICULT OR WILL NOT START Fuel Tank empty Solid State weak. CHECK: Remove Spark Plug, reattach

Plug Wire, hold Plug against engine and pull starter rope (a strong white spark should jump across plug points - weak Solid State produces a short red spark)

Solid State grounded. CHECK: Wire from Solid State to “ON-OFF’’ Switch for bare spots.

Carburetor misadjusted Engine flooded Engine is severely vapor locked

Broken Reed Valve

Fill Fuel Tank Replace C.D. Pack

Wrap Wire with electrical tape or replace

Re-adjust Carburetor Follow Starting Procedure WITHOUT USING CHOKE

ALLOW TO COOL COMPLETELY Readjust Carburetor Replace

CARBURETOR FLOODS Carburetor misadjusted Damaged Carburetor Diaphragm Leaking Gasket Leaking Inlet Needle Seat

Readjust Carburetor Rebuild Carburetor with new kit. Rebuild Carburetor with new kit. Rebuild Carburetor with new kit.

ENGINE WILL NOT IDLE Carburetor misadjusted Readjust Carburetor Carburetor Diaphragm leaking Replace Diaphragm Carburetor Inlet Seat Gasket leaking Replace Gasket Crankshaft seals leaking Replace seals Cylinder scored or compression low Replace cylinder, piston and rings Reeds leaking or broken Replace reed valve Head bound with grass Clean until free of grass

ENGINE BACKFIRES OR MISFIRES Fuel Mix improper or contaminated Drain tank and refill with freshly mixed fuel Spark Plug fouled Replace Spark Plug Solid State intermittently shorting. CHECK: loose or bare Tighten assemblies, wrap wires

Defective Reed Assembly Replace wires or loose assemblies

HEAD WILL NOT TURN WHEN THROTTLE LEVER IS SQUEEZED Shaft broken Replace shaft Head Bound with grass Clean until free

ENGINE WILL NOT ACCELERATE Carburetor misadjusted Readjust Carburetor Dirty Air Filter Clean Air Filter or replace Spark Plug fouled or Solid State weak Replace Spark Plug and regap or replace C.D. pack if we Carbon build-up Clean Exhaust Port and Muffler Carburetor Diaphragm Cover loose or Diaphragm Gasket leaking Tighten all screws Broken Reed Valve Replace

ENGINE LACKS POWER OR DIES IN THE CUT Dirty Air Filter Clean Air Filter or replace Carbon build-up Clean Exhaust Port and Muffler, page 18-6 Low compression. CHECK: Compression pressure tests Overhaul and rebuild engine

below 90 PSI or lessened engine resistance to pulling starter rope

HEAD WILL NOT ADVANCE LINE Refill with Genuine Monoflail@ Cutting Line Out of Line Bump Knob Bound Up Indexing Teeth Worn or Burred Head Dirty Line Welded

Not Enough Line Exposed

Replace Replace Clean Disassemble remove welded section and rewind line

Manually index until 4” or more of line shows per instructions

outside the head 18-5

MODELS 3100,3130,3160, 1300, 1330,1360 EXHAUST SYSTEM WALBRO CARBURETOR "WA" SERIES

MUFFLER REMOVAL

NOTE The muffler assembly should be removed periodically to inspect for excessive carbon build-up. Excess carbon deposits around the exhaust ports or exhaust exit holes will cause engine to perform in a sluggish manner.

CARBURETOR REMOVAL

1. Remove carburetor cover mounting screws.

1. Remove two muffler mounting bolts.

2. Check port area on muffler assembly for excessive carbon deposits. 2. Remove carburetor mounting screws.

3. Exhaust exit holes in muffler should be free from carbon build-up. Use small wire to clean this area when necessary.

NOTE Always use new gaskets when reinstalling muffler.

3. Disconnect fuel line from carburetor fuel inlet. Disconnect throttle wire from throttle lever.


WALBRO CARBURETOR “ W A ” SERIES DISASSEMBLY

SERVICE AND REPAIR PROCEDURES

1. Remove fuel metering cover.

2. Remove metering cover, diaphragm and gasket.

NOTE

4. The inlet lever is under spring tension. Remove inlet lever spring very carefully to prevent the loss of the spring or other parts.

NOTE

Do not stretch the spring.

The gasket and diaphragm should always be replaced.

5. Remove needle valve. Check for wear or damage. Replace if necessary.

NOTE Never use drill bits or wire to clean passages as damage will result.

3. Remove the screw, circuit plate and gasket. 6. Correct procedure to clean this carburetor is wash in solvent and blow all passages with

NOTE compressed air.

Replace this gasket.


WALBRO CARBURETOR "WA"' SERIES DISASSEMBLY

7. Remove the fuel pump cover screw.

8. Remove the pump cover gasket and diaphragm.

NOTE Always replace gasket and diaphragm when overhauling.

9. Thoroughly wash, clean the fuel filter screen and all passages before reassembling.

18-8

10. Wash in solvent and blow clean with compressed air.

NOTE: Do not use cloth towels to wipe it off. Fuzz from cloth tends to stick on the screen.

REVISED 1983

11. Diaphragms eventually deteriorate and become.. stiff with age and use. This results in an engine that may not start, hard to start or will not accelerate. Also erratic or uneven engine operation could be noted.

Diaphragms have to be soft and flexible to function properly


WALBRO CARBURETOR "WA" SERIES CARBURETION (CONT'D) WALBRO CARBURETOR

REASSEMBLY

11. Reassemble inlet needle, lever and spring.

12. Place a straight edge across carburetor body. Use a wire gauge to measure distance between straight edge and top of lever. It should be .060-.070 below straight edge.

CAUTION: Do not damage needle and seat during adjustments.

DEPRESS THEN PUSH

HERE NEEDLE HERE .060-.070 \ .0,60-.070

HIGH

14. Assemble gasket and circuit plate.

15. Assemble the metering gasket next to carburetor body. Assemble the diaphragm on the gasket. Be sure there are no wrinkles in the diaphragm.

-PRY UP HERE

LOW 16. Assemble metering cover and tighten all screws securely.

13. Adjust the lever as shown above.

If adjusted too high, engine will run rich. Too low, i t runs lean. Poor acceleration, erratic or uneven running may also be noted.


CARBURETION (CONT'D) WALBRO CARBURETOR "WA" SERIES REASSEMBLY

17. Assemble the pump diaphragm on carburetor body making sure there are no wrinkles.

20. Assemble needle valve in carburetor. Seat it very lightly and back it out one (1) full turn.

NOTE

Do not force needle into seat as damage will result, requiring replacement of carburetor body.

18. Assemble the gasket.

21. Turn idle stop screw in until point contacts throttle arm. After contact turn i t in two (2) more turns.

19. Assemble pump cover and tighten screw securely.

18-10

22. After reassembly is complete, attach a pressure gauge to the fuel inlet nipple. Introduce a pressure of 5-7 pounds to check for leaks.

It is normal for pressure to drain off very slowly in this test.

NOTE Do not exceed 8 lbs. pressure in this test.

If a rapid drop in pressure is noted, disassemble and correct.


STARTING WALBRO CARBURETOR ”WA” SERIES REASSEMBLY

For testing and adjusting a Lawn-Boy Trimmer carburetor, use an air filter cover that has been cut-away as illustrated. When in place, it deflects the hot exhaust gasses away from the carburetor air intake. These hot gasses prevents the adjusting of the carburetor correctly. It also provides access to the needle valve(s) and idle stop screw.

1. The Lawn-Boy Trimmer is equipped with a diaphragm-type carburetor. Start the engine in the following manner. The engine may be hard to start if incorrect procedure is used.

2. Place ignition switch in the “on” position.

3. Rotate choke to fully choked position.

4. When starting, operator should hold the Lawn- Boy Trimmer unit in a position so that the cutting lines are away from the person.

‘5. Depress the throttle trigger, and pull the recoil starter rope until engine pops. Once the engine has popped, rotate the choke to partial choke position.

6. Pull the recoil start rope, with throttle depressed, until engine starts. After a 5 second warm up, move choke knob to run position.

2 thru 6. 7. If engine does not start immediately, repeat steps

8. Once the engine has started, let it idle for a short

ceeding to trim. If engine won’t idle see page 18-38 for proper carburetor adjustment.

time (allowing engine to warm up) before pro-

1983 18-10A

DISASSEMBLY TILLOTSON CARBURETOR CARBURETION (CONT’D) DISASSEMBLY

1. Remove metering cover screws. 4. The brass high speed plug cannot be removed for cleaning.

TO completely clean this carburetor, it is necessary to remove the Welch plug for access to the primary and secondary circuits.

2. Remove metering cover, diaphragm and gasket.

NOTE

Always replace the diaphragm and gasket.

GASKET DIAPHRAGM COVER I \

INLET

INLET LEVER

- S C R E W SPRING 3. The inlet lever is under spring tension. Remove

inlet lever screw very carefully to prevent loss of spring or other parts.

NOTE

Do not stretch spring. SERVICE BULLETIN REFERENCES

5. Use a 3/16” drift punch and hammer to loosen the plug. Tap the plug lightly to buckle it. It should fall out.

6. CORRECT PROCEDURE to clean this carburetor is wash in solvent and blow all passages with compressed air.

NOTE

Never use drill bits or wire to clean passages as damage will result. 18-11

CARBURETION (CONT'D) TILLOTSON CARBURETOR DISASSEMBLY

7. Remove the needle valve. Inspect for damage or wear. Replace if necessary.

10. The carburetor can now be washed in solvent and all passages blown out thoroughly.

8. Remove the fuel pump cover screws.

9. Remove the pump cover, gasket and diaphragm.

11. Thoroughly wash, clean the fuel filter screen and all passages before reassembling.

10-12

NOTE

Always replace gasket and diaphragm when overhauling.

NOTE. Do not use cloth towels to wipe it off. Fuzz from cloth tends to stick on the screen.

METERING

DIAPHRAGM

12. Diaphragms eventually deteriorate and become stiff with age and use. This results in an engine that may not start, hard to start or will not accelerate. Erratic or uneven running would also be possibie.

Diaphragms have to be soft and flexible to function properly.

REVISED 1983 SERVICE BULLETIN REFERENCES

CARBURETION (CONT’D) REASSEMBLY TILLOTSON CARBURETOR

REASSEMBLY

12. I t is necessary to install a new Welch plug. Position the plug in the carburetor. Make sure i t is positioned correctly. With the 3/16” drift punch seat the plug by rapping lightly. Make sure it is secured in position.

14. To check the height of the inlet lever of the Tillotson carburetor, place a straight edge on the floor of the metering chamber above the lever. The top of the lever should be flush with the straight edge.

CAUTION: Do not damage needle and seat during adjustments.

DEPRESS THEN PUSH HERE NEEDLE

13. Reassemble inlet lever, needle and spring.

HIGH LOW 15. Adjust the lever as shown above.

If adjusted too high, engine will run rich. Too low, it runs lean. Poor acceleration, erratic or uneven running may also be noted.


TILLOTSON CARBURETOR REASSEMBLY CARBURETION (CONT'D)

16. Assemble the metering gasket, diaphragm and cover. Tighten screws securely.

NOTE

The pin on the large metal disc of the diaphragm is located on top of the inlet lever. Be sure there are no wrinkles in the diaphragm before assembling the cover.

17. Place the diaphragm on the carburetor, then the gasket and cover. Be sure there are no wrinkles in the diaphragm.

NOTE

There are two dowel pins on the cover for assembly purposes. Tighten screws securely.

18. Assemble the needle valve in carburetor. Seat it very lightly and back it out one (1) turn.

Tuen idle-stop screw in three (3) turns after contacting lever.

18-14 REVISED

NOTE

Do not force needle into seat as damage will result requiring replacement of carburetor body.

19. After reassembly is complete, attach a pressure gauge to the fuel inlet nipple. Introduce a pressure of 5-7 pounds. If a rapid drop in pressure is noted, disassemble and correct.

NOTE

Do not exceed 8 lbs. pressure in this test.

For testing and adjusting a Lawn-Boy Trimmer carburetor, use an air filter cover that has been cut-away as illustrated. When in place, it deflects the hot exhaust gasses away from the carburetor air intake. These hot gasses prevents the adjusting of the carburetor correctly. I t also provides access to the needle valve(s) and idle stop screw.

!

1983 SERVICE BULLETIN REFERENCES

5. Remove four mounting screws from reed plate and carburetor mount.

6. Check reed for freedom of movement.


8. Reed plate and carburetor mount assembly showing reed plate, reed backup and mounting screws.

NOTE

When reassembling reed plate and reed backup to carburetor mount assembly the curved portion MUST BE installed as shown.

18-15

3. Check condition of rubber mounting pads on either side of fuel tank. Replace if necessary.

4. Remove tank from shroud assembly. Check condition of tank for any rubbing or chaffing spots. Replace if necessary.

FUEL LINE Should it become necessary to replace the fuel line assembly in the fuel tank, two basic steps should be followed:

I

1. Insert fuel line assembly through hole in gas tank as shown.

2. Wiggle and pull the fuel line as shown above until the fuel filter assembly is seated. Install tank on trimming unit.

2. Check pull cord for proper spring pressure. If spring pressure is weak and an adjustment will not correct; replace spring.

3. Remove snap ring with snap ring pliers.

4. Use pliers to remove spring from its container. Be careful not to unwind spring.


POWERHEAD FLYWHEEL REMOVAL

NOTE !Be careful not to break cooling fins.

5. Place spring in starter housing as shown. Make sure outer spring catches on post.

6. When re-installing pulley, use small amount of oil on pivot location. Also grease backside of pulley where spring rides.

7. Adjust rope tension as indicated on decal located inside starter housing. One (1) turn maximum pre-tension.

8. Pull slowly on starter rope to engage starter dogs, then install the starter housing mounting screws.

1. TO remove flywheel; use Lawn-Boy tool part no. 677389 piston stop. DO NOT insert screwdriver between cooling fins. Remove flywheel nut and square drive. Use a deep socket size 5/8”

2. Use butt end of hammer or plastic mallet and tap flywheel to break loose from the main shaft.

3. Check condition of magnets for C.D. Module rubbing. If rubbing has occurred, burnish scratches.

4. Remove half-moon crankshaft key with pliers. Check key for wear.


STARTER DOG & C.D. MODULE ADJUSTMENT

1. Check condition of starter dogs for freedom

2. Torque flywheel nut to 150 in. lbs. 3. Set C.D. Module air gap by inserting Lawn-

Boy special tool part nu. 604659 between flywheel magnets and module. Secure both mounting screws on module. Air gap setting should be .010.

of movement before securing flywheel.

SHROUD & CYLINDER REPLACEMENT

1. Use a 3/16” Allen wrench to remove shroud mounting bolts.

3. Use a 3/16” Allen wrench to remove two cylinder mounting bolts.

I

4. Use a 3/32” Allen wrench to remove connecting rod’ bolt and washer. CAUTION: Do not lose mounting washer.

5. Disconnect connecting rod from crank pin.

2. Shroud mounting bolts, shroud and short 6. Remov’e cylinder and Piston assembly from block assembly illustrated. crankcase assembly.


7. Always replace and install a new gasket when replacing cylinder.

3. Remove piston rings using a circular motion. If either of these piston rings breaks, always replace both piston rings.

Examine rings for wear. Replace them, if they are worn.

8. Prior to re-assembly, make sure gasket mount ing surfaces are clean and free of all gasket material.

PISTON & CYLINDER ASSEMBLY

1. Remove piston and connecting rod assembly from cylinder.

2. Check condition of cylinder bore. If rubbing, scuffing or ridges appear, replace cylinder 5- Slip piston ring in groove as shown and and piston. check for groove wear. Refer to page 18-4 for

specifications.

SER.VICE BULLETIN REFERENCES 18-19

6. Using a feeler gauge check piston ring to piston 9. Oil rod prior to in- groove clearance. If ring clearance exceeds stallation. Make sure there are no needles miss- .005 inch, replace piston, rings and rod assem- ing or damaged bly.

10. Oil wrist pin.

7. Using feeler gauge, check ring end gap in cylinder. If it exceeds .025 inch replace piston rings. Gap should be checked at both upper and lower ends of cylinder.

W-

8. Piston ring width is an important indication of piston ring wear. If piston ring width is smaller than .052 inch replace piston rings.

11. Oil piston rings. Stagger piston ring gaps on top of piston and away from all ports.

12. Compress the rings with your fingers and insert piston into cylinder.

1 8-20 SERVICE BULLETIN REFERENCES

MAINTENANCE BUMP HEAD MODEL 3100

1. Unscrew bump knob in counterclockwise direction.

2. Remove inner spool.

3. Use rag and clean inner surface of outer spool. CAUTION: Always clean dirt from inner and outer spool before re-installing.

4. Check indexing teeth on inner and outer spool for wear. Replace if necessary.


BUMP HEAD MODELS 3130, 3160

2. Remove inner spool.

3. Use rag and clean inner surface of outer spool.

4. Check indexing teeth on inner spool for wear. Replace inner spool, if necessary. CAUTION: Always clean dirt from inner spool before re-installing.

1 18-21

INSTALLING NEW TRIMMING LINE & BUMP MAINTENANCE MODEL 1300 When installing new trimming line, a few maintenance checks should be made. The reason for doing this is to provide continuous trouble-free operation of your Bump Head. The basic maintenance cares necessary for the Bump Head are as follows: The cleaning of the inner surface of the outer spool; the cleaning of the teeth

Fig. 27 Hold outer spool with one Fig. 28 Remove inner spool. Fig. 29 Use rag and Clean inner area of the inner spool; hand and unscrew bump knob in surface of outer spool. counterclockwise direction. Inspect bump knob to be sure it can freely NOTE and frayed conditions of move axially on the captured bolt. the teeth of the inner

and also checking for worn

Always clean dirt from inner and spool. outer spool before re-installing.

If the above conditions exist, you should replace the inner spool. When winding line on inner spool, it is extremely important to wind the line in the proper direction. Failure to do so will cause the Bump Head to operate incorrectly.

Always use Genuine Monoflail

replacement line

Fig. 30 Check indexing teeth on Fig. 31 Loop new trimming line in Fig. 32 Wind 25 ft. of new cutting inner and outer spool for wear. If and around the two holes as shown line in even and tight layers. Failure necessary, replace. and wind trimming line in direction to do so may result in improper line

indicated on inner spool. operation.


INSTALLING NEW TRIMMING LINE & BUMP HEAD MAINTENANCE MODELS 1330 AND 1360

exist, you should replace the inner spool. When winding line on inner spool, it is extremely important to wind the line in the proper direction. Failure to do so will cause the Bump Head to operate incorrectly.

Always use Genuine Monoflail

replacement line Fig. 37 Check indexing teeth on Flg. 38 Loop new trimming line Fig. 39 -Wind 30 ft. of new cutting inner and outer spool for wear. If and around the two holes as shown line in even and tight layers. Failure necessary, replace. and wind trimming line in direction to do so may result in improper line

indicated on inner spool. operation.

Fig. 40 Insert trimming line into eyelet and reposition inner spool.

Fig. 41 Replace inner spool and bump knob.


CENTRIFUGAL CLUTCH MODELS 3130,3160

1. Remove three mounting screws from the clutch 4. Check condition of clutch rotor bushing and bell housing. apply light coating of grease when re-installing.

CAUTION: Do not overgrease.

MAINTENANCE DRIVE SHAFT

Remove flexible drive shaft and inspect for any excessive wear conditions.

2. Remove clutch rotor from clutch drum. Be sure not to lose thrust waster installed beneath

IMPORTANT: Anytime flexible drive shaft core is removed from outer housing, it should be cleaned and regreased with high speed, high temperature wheel bearing grease, Mobile #532 or equivalent.

NOTE After approximately every 10 operating hours, the flexible drive shaft should be reversed end for end to add additional life to the drive shaft.

3. Check clutch drum and clutch rotor for excessive wear. Replace if necessary.


FUEL & CARBURETOR MAINTENANCE AND REPAIR MODEL SSI Your Lawn-Boy Trimmer is equipped with a diaphragm type carburetor that has been carefully calibrated. In most instances no adjustment will be required by the operator. 1. Condition of air filter is very important to the operation

of the unit. The condition of the air filter should be checked on a daily basis for a dirty or clogged element. A dirty filter will restrict the air flow. upsetting the fuel- air mixture in the carburetor, resulting in symptoms often mistaken for out-of-adjustment carburetor. For air filter maintenance, see the maintenance section.

2. The carburetor has two basic adjustments, idle speed adjustment and the idle mixture adjustment. The high speed jet is a fixed jet so no high speed adjustment is necessary.

1)Remove choke cover (Fig. 6) to expose the adjustments.

2) Make initial settings with the engine stopped: See Note 1. a) Turn the idle speed screw (Fig. 7) out (counter-

clockwise); then in until the carburetor throttle lever just begins to move, continue moving two more full turns. (Waibro carburetors)

b. Turn the idle mixture screw (Fig 8) in (clockwise) until lightly seated, then turn counterclockwise one turn.

3)These initial settings should allow you to start and warm up your trimmer prior to final adjustments.

4)Release the throttle lever to let the engine idle. If the engine stops, turn the idle speed screw clockwise Vi turn at a time as required until engine maintains idle.

YOUR CARBURETOR MAY NEED ADJUSTMENT NOTE: All adjustments should be made when cutting IF YOU NOTICE ANY OF THE line is extended to its maximum cutting length. FOLLOWING CONDITIONS 5)Adjust idle speed and idle mixture screw to achieve

1) Will not idle. a) Adjust idle mixture screw for the fastest idle; then 2) Hesitates or dies on acceleration. turn counterclockwise 1/8 turn. 3) Loss of engine power which is not corrected by air filter b) Squeeze the trigger if the engine falters or hesitates

or muffler cleaning. on accelel'ation, turn the idle mixture screw counter- 4. Unit seems to operate in an erratic or fuel-rich condition clockwise 1/16 turn at a time, just enough to

(noted by excessive smoke out of the exhaust system). achieve rapid acceleration. NOTE: Careless adjustments can seriously damage c) If the idle speed has changed significantly because

your trimmer. of a) & b), above, readjust idle speed screw.

smoothest engine idle:

FUEL & CARBURETOR MAINTENANCE AND REPAIR MODEL SSll Your Lawn-Boy Trimmer is equipped with a diaphragm 2) Make initial settings with the engine stopped: see Note 1.

most instances no adjustment will be required by the wise); then in until the carubretor throttle lever just operator. begins to move, continue moving two more full 1. Condition of air filter is very important to the operation turns. (Walbro carburetors)

of the unit. The condition of the air filter should be b) Turn the idle mixture screw (Fig. 8) in (clockwise) checked on a daily basis for a dirty or clogged element. A dirty filter will restrict the air flow, upsetting the fuel- until lightly seated, then turn counterclockwise one air mixture in the carburetor, resulting in symptoms turn. often mistaken for out-of-adjustment carburetor. For warm up your trimmer prior to final adjustments. 3)These initial settings should allow you to start and air filter maintenance, see the maintenance section.

4)Release the throttle lever to let the engine idle. If the adjustment and the idle mixture adjustment. The high turn at a time as required until engine maintains idle speed jet is a fixed jet so no high speed adjustment is without the cutting head rotating. necessary.

5)Adjust idle speed and idle mixture screw to achieve YOUR CARBURETOR MAY NEED ADJUSTMENT smoothest engine idle: IF YOU NOTICE ANY OF THE a) Adjust idle mixture screw for the fastest idle; then FOLLOWING CONDITIONS turn counterclockwise 1/8 turn. 1) Will not idle. b) Squeeze the trigger if the engine falters or hesitates

type carburetor that has been carefully calibrated. In a) Turn the idle speed Screw (Fig. 7) out (counterclock-

2. The carburetor has two basic adjustments, idle speed engine stops, turn the idle speed Screw clockwise

2) Hesitates or dies on acceleration. 3) Loss of engine power which is not corrected by air filter

or muffler cleaning. 4. Unit seems to operate in an erratic or fuel-rich condition

(noted by excessive smoke out of the exhaust system). 5. Head continues to rotate at idle when the head is in

contact with the ground. NOTE: All adjustments should be made when cutting

line is extended to its maximum cutting length, and the cutting head is in contact with the ground.

1)Remove choke cover (Fig. 6) to expose the adjustments.

on acceleration, turn the idle mixture screw counterclockwise 1/16 turn at a time, just enough to achieve rapid acceleration.

(1) High enough to disengage the centrifugal clutch

d) Recheck for proper operation, repeat steps b) and

NOTE: The weight of the head and wand when in contact with the ground should stop the head from rotating. Because the head rotates on antifric- tion bearings, it is normal for the head to rotate when not in contact with the ground.

c) Adjust idle speed.

and stop the head from rotating.

c) above,' if necessary

SSI SSll MAINTENANCE AIR FILTER NOTE:

Fig. Remove carburetor cover mounting screws.

Fig. 2 Remove filter from carburetor cover.

CLEAN AND RE-OIL AIR FILTER EVERY 10 HOURS

Your unit's air filter is one of the most important areas to maintain. If the air filter is not cared for as described on the carburetor cover or as shown in Figs. 1 thru 5, you will void your warranty.

Fig. 3 -Wash filter in kerosene, petroleum solvent or detergent.

Fig. 5 Squeeze filter to spread oil and re-install in carburetor cover. engine oil.

Fig. 4 Squeeze dry and re-oil air filter with SA€ 30

CARBURETOR ADJUSTMENTS MAINTENANCE AND REPAIR (CON'T)

Fig. 7 View showing idle speed adjustment screw


Fig. 8 View showing idle mixture adjustment with cut-a-way air filter cover in place.

NOTE:

When closing idle mixture adjustment screw, turn finger-tight only. Forcing adjustment screw with screwdriver will cause serious damage to seat.

STARTING WALBRO CARBURETOR REASSEMBLY SSI SSII

For testing and adjusting a Lawn-Boy Trimmer carburetor, use & air filter cover that has been cut-away as illustrated. When in place, it deflects the hot exhaust gasses away from the carburetor air intake. These hot gasses prevents the adjusting of the carburetor correctly. It also provides access to the needle valve(s) and idle stop screw.

1.

2.

3.

4.

5.

6.

7.

8.

The Lawn-Boy Trimmer is equipped with a diaphragm-type carburetor. Start the engine in the following manner. The engine may be hard to start if incorrect procedure is used.

Place ignition switch in the “on” position.

Rotate choke to fully choked position.

When starting, operator should hold the Lawn- Boy Trimmer unit in a position so that the cutting lines are away from the person.

Depress the throttle trigger, and pull the recoil starter rope until engine pops. Once the engine has popped, rotate the choke to partial choke position.

Pull the recoil start rope, with throttle depressed, until engine starts. After a 5 second warm up, move choke knob to run position.

If engine does not start immediately, repeat steps 2 thru 6.

Once the engine has started, let it idle for a short time (allowing engine to warm up) before proceeding to trim. If engine won’t idle see page 18-38 for ,proper carburetor adjustment.

18-27A 1983

SSI SSll

Fig. 10 Disconnect fuel line from carburetor fuel inlet.

FOR CARBURETOR REPAIR AND SERVICE REFER TO PAGES 18-6 THROUGH 18-15.

Fig. 11 Make sure no foreign material has clogged reed plate passages.

Fig. 13 Check reed for freedom of movement.

Fig. 15 Reed plate and carburetor mount assembly showing reed plate, reed backup and mounting screws.

Fig. 12 Remove four mounting screws from reed plate and carburetor mount.

Fig. 14 To replace reed if necessary, remove two mounting screws as shown

REED BACKUP PLATE MUST BE FLUSH WITH REED BLOCK WHEN ASSEMBLED

NOTE

carburetor mount assembly the curved portion MUST Fig. 16 When reassembling reed plate and reed backup to

BE installed as shown.


ENGINE REMOVAL when necessary.

outer cowls. Fig. 21 Remove all the phillips mounting screws holding

direction until free of clamp Fig. 22 Unscrew head adjustment counterclockwise

Fig. 23 -Turn trimmer over and remove the side opposite the gas tank filler.

NOTE

Routing and assembly of the following for reassembly: fuel line, throttle return spring, throttle wire housing, switch and wire routing.

Fig. 24 -With the left side removed proceed to lift from the housing handle area, the switch and lead assembly, the throttle lever and spring, and the throttle wire housing. Also loosen the fuel line from the retaining groove in the starter housing.

Fig. 25 -Trimmer shown with throttle, ignition switch and gas tank disconnected.

STARTER HOUSING

Fg. 28 Checking pull cord for proper spring pressure if spring pressure is weak and an adjustment will not work (Fig. 29), it will be necessary to replace spring.

Fig. 27 Remove four mounting screws from starter housing.

Fg. 29 Adjust rope tension as indicated on decal located inside starter housing.


Fig. 31 Check condition of starter dogs for freedom of movement before securing flywheel.

18-30

Fig. 30 -'Pull slowly on starter rope to engage starter d o g s , then install the starter housing mounting screws (ref. Fig. 27).

Fg. 32 -:Set C.D. Module air gap by inserting alr gap gauge (604659) between flywheel magnet and module. Secure both mounting screws on module. Air gap setting should be .010.015.

ITEM PART NO. PART NAME 1 610360 Pull handle 2 610301 Rope 3 610302 Recoil spring 4 682030 Recoil pulley assembly 5 682540 Starter housing assembly 6 682541 Upper clamp assembly 7 682307 Flywheel assembly 8 610303 Square drive nut 9 682498 Module assembly

10 682542 Switch assembly 11 682543 Wire leads assembly 12 682544 Shroud assembly 13 682545 Fuel cap assembly 14 682546 Pulley retainer assembly 15 611000 Fuel tank 16 611058 Fuel tank vent 17 682547 Fuel line assembly 18 610308 Outer bearlng

20 610309 Seal 19 682040 Snap ring assembly

21 682041 Inner bearlng assembly 22 611059 Crankcase 23 682548 Cyllnder assembly 24 610311 Spark plug

ITEM PART NO. PART NAME 25 682502 Piston & rod assembly 26 682549 Power shaft assembly 27 61 1060 Shroud extension 28 682046 Reedassembly 29 682550 Carburetor mount assembly 30 682048 Throttle adjustment assembly 31 682310 Carburetor assembly (Walbro)

682551 Carburetor assembly (Tlllotson) 32 610312 Air cleaner fllter 33 682505 Carburetor mounting screw assembly

35 682313 Choke knob assembly 34 682312 Air cleaner cover assembly

36 682311 Muffler assembly 37 682054 Muffler mounting bolt assembly

*38 682055 Engine gasket kit *39 682552 Engine hardware kit *40 682057 EOM carburetor repair kit (Walbro) *41 682058 Gasket-Diaphragm repair kit (Walbro) *42 682507 Piston ring set *43 682553 Carburetor repalr kit (Tillotson) 44 611001 Right side cowl 45 611002 Lett side cowl

ENGINE MODELS ss I ss II

ITEM PART NO.PART NAME 48 682555 Engine mount assembly 49 611062 Grommet tube 50 611004 Throttle trigger assembly 51 611005 Head adjustment knob

53 611063 Ground tab 52 682556 Throffle wire assembly

*71 682557 Short block assembly (Items 18-26) 72 610672 Exhaust gasket(10 pack) 73 610674 Cylinder gasket (10 pack) 74 610675 Carburetor gasket (10 pack) 75 610676 Flywheel key (10 pack)

(A) *76 682558 Crankcase service assembly (Items 18-22,26)

"NOT SHOWN

*29 610673 Carburetor mount gasket (10 pack)

ITEM PART NO. PART NAME 45 682060 Lower clamp assembly 46 682061 Blade assembly 47 611003 D-handle 48 682559 D-handle hardware assembly

*49 682561 Shoulder strap klt 50 682064 Flexible drive shaft 51 682562 Drive shaft housing assembly 52 682066 Guard and bearing housing assembly 53 610303 Square drive nut 54 682348 Spool shaft assembly 55 682068 Outer spool assembly 56 610317 Spring 57 610318 Inner reel

*59 610375 Monoflall cutting line 50 ft (2 fills) 58 682069 Bump head knob assembly

'60 610977 Monoflail cuttlng line 1 Ib. (16 fills) 61 610660 Retainer (10 pack) 62 610682 Eyelet 63 610996 Washer

*NOT SHOWN

18-32

ITEM PART NO. PART NAME 45 682660 Lower clamp assembly 46 682061 Blade assembly 47 611064 D-handle 48 682559 D-handle hardware 49 682560 Handle grlp assembly 50 682064 Flexible drive shaft 51 682070 Clutch houslng assembly 52 682071 Clutch rotor assembly 53 682072 Clutch drum assembly 54 610319 Lower guard 55 610320 Lower bearing housing 56 682316 Lower drive shaft assembly 57 610683 Spool retainer (1 0 pack) 58 610635 Outer spool 59 610636 Sprlng 60 610637 Inner reel 61 682350 Bump head knob assembly 62 610682 Eyelet 63 682563 Drive shaft housing assembly

*64 682561 Shoulder strap kit *65 610376 Monoflall cuttlng line 30 A *66 610978 Monoflall cutting line 1 Ib.

SS II TRIMMER PARTS

*NOT SHOWN

18-33

GASOLINE POWERED GRASS & WEED TRIMMER with Bump Head Line Release

18-34 1983

Fig. 3-Loosen all four corners of Split Boom Coupling as to allow lower portion of Boom to be assembled.

Fig. 4-Insert loose end of Flex Drive Shaft into upper portion of Trimmer Boom. It may be necessary to rotate Cutting Head Assembly to be sure Flex Shaft is properly engaged into engine portion of Trimmer Boom.

Fig. 5-Check sight hole, as shown, to make sure both ends of Trimmer Boom are together and that Pin of Coupling is in hole of Lower Boom.

Fig. 6-Tighten the three corner screws and the thumb screw before trimming.

Fig. 7-Remove “D’ handle from package. Spread and twist “D” handle enough to interlock tabs as it is being installed over tube. Install bolt, washer and wing nut and tighten.

_.-

Fig. 8-Insert guard onto steel tube above clamp assembly as shown.

Fig. 9-Drop guard down to top of aluminum bearing housing and rotate guard into proper position.

Fig. 10-Drop small amount of oil onto guard screws to ease their installation.

Fig. 11-Tighten all four guard screws before running unit.

NOTE: Guard must be installed before operation of weed trimmer. 18-35

PRE-OPERATION CHECK & FUEL

Be sure to read this section carefully before attempting to operate this unit. 1. Fill fuel tank with oil and gas mixture as indicated on red fuel tag

2. Always make sure gasoline cap is tightened securely before located on gas tank. (Fig. 12)

attempting to start engine.

AD CAREFULLY LAWN BOY 2CYCLE OIL IS RECOMMENDED

FOR THIS LAWN BOY TRIMMER Lawn-Boy 2 cycle oil is formulated specifically for high performance, two cycle engines. Special additives promote thorough mixing and ready combustion. This gives the engine the benefits of clean, fresh lubrication every revolution of the crankshaft. Thoroughly mix contents of one 8-oz Lawn-Boy 2 cycle oil can with two U.S. gallons of regular grade automotive gasoline. Do not mix directly in engine fuel tank. If you use two cycle oil other than Lawn-Boy 2 cycle oil, a mixture of 6 oz. oil to 1 gal. gasoline is recommended.

Do not use a synthetic base oil for lubrication In Lawn-Boy Gasoline Trimmers. Remember to pay strict attention to the fuel mixing instructions. DO NOT use no-lead fuel, fuel containing alcohol or fuel labeled “Gasohol”. DO NOT use a 40:l ratio. NOT FOLLOWING MIXING PROCEDURE CAN CAUSE ENGINE TO SEIZE.

SAFETY WARNING

Gasoline is extremely flammable and highly explosive under certain conditions. Always stop engine, and do not smoke or allow open flame spark when refueling.

Fig. 12-Fuel decal located on gas tank.

8 oz. 2 gallons Lawn-Boy 2 cycle oil regular gas

LAWN-BOY 2 CYCLE OIL

READ CARFULLY 5. Depress the throttle trigger, or engage throttle lock, and pull the recoil starter rope until engine pops. Once the

MIXING RATIO

1. The Lawn Boy Trimmer is equipped with a diaphragm- type carburetor. Start the engine in the following manner. The engine may be hard to start if incorrect procedure is used.

2. Place ignition switch in the “on” position. (Fig. 13) 3. Rotate choke to fully choked position. (Reference

engine has popped, rotate the choke to partial choke position. (Fig. 14)

6. Pull the recoil start rope, with throttle depressed, until engine starts. After a 5 second warm up, move choke knob to run position. (Fig. 14)

7. If engine: does not start immediately, repeat steps 2 thru 6.

STARTING WA,LBRO CARBURETOR REASSEMBLY

For testing and adjusting a Lawn-Boy Trimmer carburetor, use an air filter cover that has been cut-away as illustrated. When in place, it deflects the hot exhaust gasses away from the carburetor air intake. These, hot gasses prevents the adjusting of the carburetor correctly. It also provides access to the needle valve(s) and idle stop screw.

1. The Lawn-Boy Trimmer is equipped with a diaphragm-type carburetor. Start the engine in the following manner. The engine may be hard to start if incorrect procedure is used.

2. Place ignition switch in the “on” position.

3. Rotate choke to fully choked position.

4. When starting, operator should hold the Lawn- Boy Trimmer unit in a position so that the cutting lines are away from the person.

5. Depress the throttle trigger, or engage throttle lock and pull the recoil starter rope until engine pops. Once the engine has popped, rotate the choke to partial choke position.

6. pull the recoil start rope, with throttle depressed, until engine starts. After a 5 second warm up, move choke knob to run position.

2 thru 6. 7. If engine does not start immediately, repeat steps

8. Once the engine has started, let it idle for a short time (allowing engine to warm up) before pro- ceding to trim. If engine won’t idle see page 18-38 for proper carburetor adjustment.

1983 18-37

FUEL & CARBURETOR ADJUSTMENT Your Lawn Trimmer is equipped with a diaphragm 1) Remove choke cover (Fig. 16) to expose adjust- type carburetor that has been carefully calibrated. In most ments. instances no adjustment will be required by the operator. 2) Make initial with the engine stopped These 1. Condition of air filter is very important to the operation initial settings should allow you to start and warm up

of the unit. The condition of the air filter should be your trimmer prior to final adjustments. checked on a daily basis for a dirty or clogged element. a) Turn the idle speed screw (Fig. 17) out coun- A dirty filter will restrict the air flow, upsetting the fuel-air terclockwise), then in until the carburetor throttle mixture in the carburetor, resulting in symptoms often lever just begins to move; continue moving two mistaken for out-of-adjustment carburetor. For air filter more full turns. maintenance, see the maintenance section. b) Turn the idle mixture screw (Fig. 18) in (clockwise)

2. The carburetor has two basic adjustments, idle speed adjustment and the idle mixture adjustment. The high

until lightly Seated, then turn counterclockwise one and one half turns.

speed jet is a fixed jet so no high speed adjustment is 3) Start and warm up the trimmer. necessary. 4) Release the throttle lever to let the engine idle. If the

YOUR CARBURETOR MAY NEED ADJUSTMENT engine Stops, turn the idle speed screw clockwise 1/8 IF YOU NOTICE ANY OF THE turn at a time as required until engine maintains idle. FOLLOWING CONDITIONS NOTE: All adjustments should be made when cutting lines

1) Will not idle. Adjustments must be made quickly, as running with choke 2) Hesitates or dies on acceleration. cover removed for more than two minutes will cause the 3) LOSS of engine power which is not corrected by air filter carburetor to Over heat, causing erratic operation.

4) Unit Seems to operate in an erratic or fuel-rich condition 5) Adjust idle speed and idle mixture Screw to achieve

are extended to their maximum cutting length.

or muffler cleaning.

(noted by excessive smoke out of the exhaust system). smoothest engine idle: a) Adjust idle mixture screw for the fastest idle; then

your trimmer. b) Squeeze the trigger if the engine falters or hesitates on acceleration, turn the idle mixture screw counterclockwise 1/16 turn at a time, just enough to achieve rapid acceleration.

c) If the idle speed has changed significantly because of a) 8, b) above. readiust idle weed screw.

NOTE: Careless adjustments can seriously damage turn counterclockwise 1/8 turn.

Fig. 16-Unscrew mounting screws and remove choke cover assembly.

Fig. 18-View showing low speed mixture carburetor adjustment.

When closing low speed mixture screw, turn NOTE finger-tight only. Forcing adjustment screw with

screwdriver will cause serious damage to seat.

Fig. 17-View showing idle speed adjustment screw. 18-38

STOPPING The Lawn Boy Trimmer is equipped with an ignition type on/off switch (Fig. 12). Engine stopping is accomplished by moving the switch lever to the “off’ position, causing the engine to stop.

Fig. 19-Ignition switch for stopping the engine.

TRIMMING LINE ADJUSTMENT & BUMP HEAD Your Lawn Boy Trimmer has been designed with a Bump Head™ or automatic trimming line release system. The basic principle behind the automatic line release system is the use of centrifugal force. Centrifugal force is gener- ated on the cutting line when the unit is in a spinning operation. Therefore, in order to release line automatically, the unit must be running. The best r.p.m. range when tapping and releasing the line is a high engine speed. This feature enables the operator to release more trimming line without stopping the engine. As the line becomes frayed and worn, additional line may be released by lightly tapping the unit on the ground. Each time the unit is bumped, approximately 1” of trimming line will be released. The unit is also equipped with a weed guard that has built in an automatic line cutting blade. this merely means that if excessive line is released, it will be automatically cut to the proper length. when tapping the unit on the ground for more line release, it should be done on bare ground or hard soil. If it is attempted in tall grass, the unit will probably stall.

Fig. 20-Operator bumping head in a downward direction to extend more trimming line. NOTE: The trimmer must be operating at high engine speed to release more line.

Fig. 21-Decorative scalping is accomplished by removing all vegetation around trees, posts, fences, etc Use 30-degree angle when trimming in this method.

INSTALLING NEW TRIMMING LINE & BUMP HEAD MAINTENANCE

When installing new trimming line, a few maintenance checks should be made. The reason for doing this is to provide continuous trouble-free operation of your Bump Head. The basic maintenance cares necessary for the Bump Head are as follows: The cleaning of the inner surface of the outer spool; the cleaning of the teeth area of the inner spool; and also checking for worn and frayed conditions of the teeth of the inner spool

If the above conditions exist, you should replace the inner spool. When winding line on inner spool, it is extremely important to wind the lines in the proper direction. Failure to do so will cause the Bump Head to operate incorrectly.

A dual line replacement cartridge is available at your Lawn Boy Dealer. replacement l ine

Always use Genuine NOTE! Monoflail ™

Monoflair

Fig. 26-Hold outer spool with one hand and unscrew bump knob in counterclockwise direction. Inspect bump knob to be sure it can freely move axially on the captured bolt.

Fig. 29-Check indexing teeth on inner and outer spool for wear. If necessaiy, deburr or replace.

Fig. 27-Remove inner spool. NOTE: and outer spool and shaft before

Always clean dirt from inner

re-installing.

Fig. 30-Loop new trimming line into Fig. 31-Wind approx. 25 ft of new two equal lengths and around the cutting line in even and tight layers. two holes as shown and wind Be sure not to overlap the two trimming line in direction indicated separate lines. Failure to do so may on inner spool. result in improper line operation.

Fig. 32-After the new trimming line has been tightly & properly wound around spool, insert each end of the new line in opposite slots provided to hold line.

18-40

Fig. 33-With each end of the new Trimmer Line in their respective holding slots, insert the lines into the eyelets, install inner spool as shown, pulling the lines carefully to outside. Grasp both lines and pull to release the lines from the holding slots in the spool.

Fig. 34-Hold outer spool with one hand and unscrew bump knob in counterclockwise direction. Inspect bump knob to be sure it can freely move axially on the captured bolt.

MAINTENANCE AIR FILTER NOTE:

CLEAN AND RE-OIL AIR FILTER EVERY 10 HOURS

Your unit's air filter is one of the most important areas to maintain. If the air filter is not cared for as described on the carburetor cover or as shown in Figs. 35-38, you will void your warranty.

Fig. 34-Remove filter from carburetor cover. Fig. 35-Wash filter in kerosene, petroleum solvent or detergent.

Fig. 36-Squeeze dry and re-oil air filter with SAE Fig. 37-Squeeze filter to spread oil and re-install 30 engine oil. in carburetor cover.

MAINTENANCE DRIVE SHAFT After apporoximately every 10 hours of continuous use.

NOTE the flexible drive shaft should be reversed end for end to add additional life to the drive shaft.

Fig. 38-Remove flexible drive shaft and inspect Fig. 39-IMPORTANT Anytime flexible drive shaft core is for any excessive wear conditions. removed from outer housing, it should be cleaned and

regreased with high speed, high temperature wheel bearing grease, Mobil #532 or equivalent.

18-41

ITEM 1 2 3 4 5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33

18-42

PART NO. 610300 610301 61 0302 682030 683064 682032 682307 61 0303 682498 611714 145307 683065

682546 145308

683066 683067 682039 610308 682040 610309 682041 145563 61 1735 61 031 1 153302 153303 683078 682046 682504 682048 683063 61 031 2 682505

Shroud assembly 39 683069 Front mounting pad '40 682552 Pulley retainer assembly *'41 153307 Cap and vent assembly '42 153308 Engine cover & decal assembly '43 153309 Fuel line assembly '44 682507 Outer bearing '45 683099 Snap ring assembly '46 153311 Seal 47 610672 Inner bearing assembly 48 145564 Crank case 49 683070 Cylinder assembly 50 611063 Spark plug Piston and rod assembly

Shroud extension and stand Power shaft assembly

Reed assembly Carburetor mount assembly Throttle adjustment assembly Carburetor assembly Air cleaner filter Carburetor mounting screw assembly

Switch assembly Engine hardware kit Engine gasket kit O.E.M. carburetor repair kit Gasket diaphragm repair kit Piston ring set Short block assembly Crank case service' assembly Exhaust gasket (10 pack) Cylinder gasket (10 pack)

Ground tab Engine cover mounting screw assembly

'Not shown

TORQUE SPECIFICATIONS (Cold Engine)

Cylinder bolts 120 in. Ibs. Muffler bolts 56 in. Ibs. Carburetor mount mounting bolts 15 in. Ibs. Carburetor mounting bolts 40 in. Ibs. Shroud mounting bolts 120 in. Ibs. Module mounting screws 28 in. Ibs. Starter housing screws 40 in. Ibs. Air cleaner cover mounting screws 40 in. Ibs. Flywheel nut Spark plug

150 in. Ibs. 150 in. Ibs.

ITEM 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78

*'79 '80 '81 '82

PART NO. 610313 682062 61 031 5 153316 610314 611715 153317 683071 683072 683073 683074 611716 682060 682064 145570 145567 153312 145565 682061 153318 145569 15331 3 683075 145566 61 031 7 61 0660 610318 682069 61 0375 610977 683062 683059

PART NAME Main handle grip Throttle cable housing assembly Throttle cable Throttle trigger assembly Throttle trigger spring D-handle

Upper drive shall housing assembly D-handle hardware assembly

Split boom coupling set Lower drive shall housing assembly

Adjustment knob Coupling bolt assembly

Lower clamp assembly Flexible drive shall

Washer Retaining ring

Bushing housing assembly Guard Blade assembly Guard mounting screw assembly Anti-rotation screw Spool shaft Outer spool Eyelet Spring Retainer (10 pack) Inner reel Bump head knob assembly Monoflail cutting line 50 ft (2 fills) Monoflail cutting line 1 Ib (16 fills) Dual line cartridge replacement Complete cutting head (twin line)

'Not shown

PARTS MODEL 1400

1400 & 1460 SERIES TROUBLE SHOOTING

NOTE

NOTE: If you do not understand, or feel you are inca- pable of properly correcting any problem described here, please contact your nearest Lawn Boy Service Center. Improper servicing can be dangerous and expensive to you as a customer.

TROUBLE SHOOTING POSSIBLE CAUSE AND CHECK POSSIBLE REMEDY

STARTER ROPE WILL NOT REWIND Contact your nearest L/B Service Center Broken Starter Spring/Not enough Preload Adjust tension per decal on inside of starter housing Broken pulley Replace

STARTER DOES NOT ENGAGE FLYWHEEL Broken Pawl Spring Contact your nearest L/B Service Center

Contact your nearest L/B Service Center

Fuel Tank empty Fill Fuel Tank Solid State weak. CHECK: Remove Spark Plug, reattach Contact your nearest L/B Service Center

Plug Wire, hold Plug against engine and pull starter rope (a strong white spark should jump across plug points-weak Solid State produces a short red spark)

“ON-OFF’ Switch for bare spots. Solid State grounded. CHECK: Wire from Solid State to Wrap Wire with electrical tape or replace

Carburetor misadjusted Follow Carburetor Adjusting Procedure Engine flooded Follow Starting Procedure WITHOUT USING CHOKE Engine is severely vapor locked ALLOW TO COOL COMPLETELY, then follow Starting

Ignition Switch in Off Position Put switch in On Position Broken Reed Valve Contact your nearest L/B S

Carburetor misadjusted Follow Carburetor Adjusting Procedure Damaged Carburetor Diaphragm Contact your nearest L/B Service Center Leaking Gasket Contact your nearest L/B Service Center

Contact our nearest L/B Service Center

Instructions, page 5

Carburetor misadjusted Follow Carburetor adjusting Procedure Carburetor Diaphragm leaking Contact your nearest L/B Service Center Carburetor Inlet Seat Gasket leaking Contact your nearest L/B Service Center Crankshaft seals leaking Contact your nearest L/B Service Center Cylinder scored or compression low Contact your nearest L/B Service Center Reeds leaking or broken Contact your nearest L/B Service Center

an until free

TROUBLE SHOOTING CONTINUED POSSIBLE CAUSE AND CHECK POSSIBLE REMEDY

ENGINE BACKFIRES OR MISFIRES Fuel Mix improper or contaminated Drain tank and refill with freshly mixed fuel Spark Plug fouled Clean Spark Plug and regap or replace Solid State intermittently shorting. CHECK: loose or bare Tighten assemblies, wrap wires

Defective Reed Assembly Contact your nearest L/B Service Center

Shaft broken Replace shaft Flex Shaft not engaged Re-assemble properly

wires or loose assemblies

HEAD WILL NOT TURN WHEN THROTTLE LEVER IS SQUEEZED

ENGINE WILL NOT ACCELERATE Carburetor misadjusted Foilow Carburetor Adjusting Procedure Dirty Air Filter Clean Air Filter or replace Spark Plug fouled or Solid State weak Clean Spark Plug and regap or replace Carbon build-up Clean Exhaust Port and Muffler Carburetor Diaphragm Cover loose or Diaphragm Gasket leaking Contact your nearest L/B Service Center Broken Reed Valve Contact your nearest L/B Service Center

ENGINE LACKS POWER OR DIES IN THE CUT Dirty Air Filter Clean Air Filter or replace Carbon build-up Clean Exhaust Port and Muffler, page 18 Low compression. CHECK: Compression pressure tests Contact your nearest L/B Service Department

below 90 PSI or lessened engine resistance to pulling starter rope

HEAD WILL NOT ADVANCE LINE Out of Line Refill with Genuine Monoflail® Cutting Line Bump Knob Bound Up Replace Indexing Teeth Worn or Burred Replace Head Dirty Clean Line Welded or Dis,assemble, remove welded section and rewind line Line Twisted When Refilled per instructions Not Enough Line Exposed Manually index until 4 of line shows

outside the head.

ENGINE SPECIFICATION S Spark plug gap .025

Flywheel torque 150 in. Ibs. C. D. Module air gap .010-.015 Piston ring end gap .025 max. Piston side ring clearance .005 max. Compression avg. 120 Ibs.; min. 90 Ibs. Piston ring width .052 min. Spark plug Champion DJ8J

Fig. 1-Remove Screw, Spark Plug Wire & Shroud Fig. 2-Remove (2) Wire Leads at Ignition Module. Extension Stand. Be sure that wire leads are secured in retainer slot

before reassembly. 18-45

...

ENGINE COVER REMOVAL (CON’T.)

MUFFLER The muffler assembly should be removed periodically to inspect for excessive carbon build-up. Excess carbon deposits around the exhaust ports or exhaust exit holes will cause engine to perform in a sluggish manner.

Fig. 4-Slide Cover forward on Boom as Starter Handle is tucked thru opening. Remove Cover.

Fig. 5-Remove two muffler mounting bolts. Fig. 6-Check port area on muffler assembly for excess carbon deposits.

18-46

STARTER HOUSING

Fig. 1-Remove four mounting screws from starter Fig. 2-Check pull cord for proper spring pressure. If housing. spring pressure is weak and an adjustment will not work

(Fig. 3), it will be necessary to have dealer replace spring.

Fig. 3-Adjust rope tension as indicated on decal located Fig. 4-Pull slowly on starter rope to engage starter inside starter housing. dogs, then install the starter housing mounting screws

(ref. Fig. 1).


Fig. 5-Check condition of starter dogs for freedom of Fig. 6-Set C. D. Module air gap by inserting air gap movement before securing flywheel. gauge (604659) between flywheel magnet and module.

Secure both mounting screws on module. Air gap setting should be ,010 ,015.

M O D E L 1400 FUEL SYSTEM

WT-II WALBRO CARBURETOR

Fig. l-Remove carburetor cover moun- Fig. 2-Remove carburetor mounting Fig. 3-Disconnect fuel line and throttle ting screws. screws. cable from carburetor.

Fig. 4-Make sure no foreign material has Fig. 5-Remove four mounting screws Fig. 6-Check reed for freedom of clogged reed plate passages. from reed plate and carburetor mount. movement.

Fig. 9-Check condition of rubber mounting pads on either side of fuel tank. Replace if necessary.

18-48 fuel leaks.

CARBURETION (CON'T.) WT-II WALBRO CARBURETOR DISASSEMBLY

Fig. 13-Remove Fuel Metering cover.

NOTE: The gasket and diaphragm should always be replaced.

Fig. 15-The inlet lever is under spring tension. Remove inlet lever assembly very carefully to prevent loss of spring or other parts.

NOTE DO NOT STRETCH SPRING.

Fig. 16-Remove needle valve. Check for wear or damage. Replace i f necessary.

Fig. 18-Correct procedure to clean this carburetor is wash in solvent and blow all passages with compressed air.

NOTE Never use drill bits or wire to clean passage as damage will result.

Fig. 17-To completely clean this carburetor, it is necessary to remove both welch plugs.

1983 I983 18-49

CARBURETION (CONT'D.) WT-II WALBRO CARBURETOR DISASSEMBLY

Fig. 19-Remove fuel pump cover screw. Fig. 20-Remove the pump cover gasket and diaphragm.

NOTE Always replace gasket and diaphragm when overhauling.

Fig. 21-Diaphragms eventually deteriorate and become stiff with age and use. The results may be an engine not starting; hard to start or will not accelerate. Also erratic or uneven engine operations could be noted. Diaphragms have to be soft and flexible to function properly.

Fig. 22-Thoroughly wash, clean the fuel filter screen and all passages before 'reassembling. Wash in solvent and blow clean with compressed air.

NOTE Do not use cloth towels to wipe it off. Fuzz from cloth tends to stick on the screen.

Fig. 23-Reassemble inlet needle, lever and spring.

18-50 1983

CARBURETION (CONT'D.) WT-II WALBRO REASSEMBLY

CAUTION Do not damage needle and seat during adjustments.

DEPRESS THEN PUSH

HERE NEEDLE HERE 060-070 \ .0,60-.070 I

HIGH LOW

Fig. 27-Assemble the metering gasket next to carburetor body. Fig. 28-Assemble metering cover and tighten all screws Assemble the diaphragm on the gasket. Be sure there are no securely. wrinkles in the diaphragms.

Fig. 29-Assemble the pump diaphragm and gasket on carburetor body making sure there are no wrinkles.

1983 18-51

CARBURETION (CONT'D.)

Fig. 31-Assemble pump cover and tighten screw securely.

WT-ll WALBRO CARBURETOR REASSEMBLY

Fig. 32-Assemble needle valve in carburetor. Seat it very lightly and back it out one and a half (1 112) turns.

NOTE Do not force needle into seat as damage will result requiring replacement of carburetor body.

Fig. 33-Turn idle stop screw out counterclockwise, then in until the carburetor throttle lever just begins to move; continue moving 2 more full turns.

These initial settings on the Idle speed and idle mixture should allow you to start and warm up the trimmer prior to final adjustments.

Fig. 34-Af ter reassembly is complete attach a pressure gauge to the fuel inlet nipple. Introduce a pressure of 5 7 Ibs. to check for leaks.

N O T E It is normal for pressure to drain off very slowly in this test.

NOTE Do note exceed 8 Ibs. pressure in this test. If a rapid drop in pressure is noted disassemble and correct.

18-52 1983

CARBURETION (CONT'D) M O D E L 1460 TRIMMER

34. A different carburetor is used on the Model 1460 Trimmer, it is a Walbro WT-12 which controls the high speed of the engine with a built-in governor.

36. The governor assembly itself Is sealed and can not be disassembled. However the complete assembly can be removed from the carburetor for normal cleaning and blowing out passages in the carbureteor.

35. When engine speed reaches 8500 8800 RPM, vibrations from the higher speed causes a spring loaded ball check valve to move off its seat which opens another fuel passage. The extra fuel flowing from this passage into the air stream creates a richer mixture which reduces the engine speed slightly.

For repairs and adjustments refer to Servicing Information on the WT-ll Walbro Carburetor.

37. After reassembly i s complete, attach a pressure gauge to the fuel inlet nipple. Introduce a pressure of 5-7 pounds. If a rapid drop in pressure is noted, disassemble and correct.

1983 18-53

STARTING WALBRO CARBURETOR REASSEMBLY, TESTING AND ADJUSTMENTS

?- For testing and adjusting a Lawn-Boy Trimmer carburetor, use an air filter cover that has been cut-away as illustrated. When in place, it deflects the hot exhaust gasses away from the carburetor air intake. These hot gasses prevents the adjusting of the carburetor correctly. It also provides access to the needle valve(s) and idle stop screw.

1.

2.

3.

4.

5.

6.

7.

8.

The Lawn-Boy Trimmer is equipped with a diaphragm-type carburetor. Start the engine in the following manner. The engine may be hard to start if incorrect procedure is used.

Place ignition switch in the “on” position.

Rotate choke to fully choked position.

When starting, operator should hold the Lawn- Boy Trimmer unit in a position so that the cutting lines are away from the person.

Depress the throttle trigger and pull the recoil starter rope until engine pops. Once the engine has popped, rotate the choke to partial choke position.

pull the’ recoil start rope, with throttle depressed, until engine starts. After a 5 second warm up, move choke knob to run position.

If engine does not start immediately, repeat steps 2 thru 6 . . Once the engine has started, let it idle for a short time (allowing engine to warm up) before proceeding to trim. If engine won’t idle see page 18-38 for proper carburetor adjustment.

18-54 1983

“I

4600

7231 5249

7270 R7270 7270AE

R7270AE

8240 R8240 8240AE

R8241AE 8290

INCLUDES THESE MODELS

SUPREME 20” Push With Rear Catcher 4600 19” Push W/O Catcher 5253 21” Push W/O Catcher 7232 21” Push With Side Catcher 7271 21” Push With Rear Catcher R7271 21” Push With Side Catcher, El. St. 7271AE 21” Push With Rear Catcher, El. St. R7271 AE

8125 21” S. P. With Side Discharge 8241 21” S. P. With Rear Discharge R8241 21” S. P. With Side Discharge, El. St. 8241AE 21” S. P. With Rear Discharge, El. St. R8241AE 21” S. P. W/O Catcher 8291

20” Push With Rear Catcher 19” Push W/O Catcher 21” Push W/O Catcher 21” Push With Side Catcher 21” Push With Rear Catcher 21” Push With Side Catcher, El. St. 21” Push With Rear Catcher, El. St. 20” S. P. Rear Discharge 21” S. P. With Side Discharge 21” S. P. With Rear Discharge 21” S. P. With Side Discharge, El. St. 21” S. P. With Rear Discharge, El. St. 21” S. P. W/O Catcher

MULCH-R-CATCH 4573 21” Push With Rear Catcher 8673 21” S. P. With Rear Catcher 8674 21” S. P. With Rear Catcher 8673AE 21” S. P. With Rear Catcher, El. St.

SCAMP 4250 20” Push W/O Rear Catcher 4251 20” Push W/O Rear Catcher 4505 20” Push W/O Catcher 4506 20” Push W/O Catcher 8605 20” S. P. W/O Catcher 8606 20” S. P. W/O Catcher 4250 20” Push W/O Rear Catcher

COMMERCIAL 6261 21” Push W/O Catcher 6262 21” Push W/O Catcher 6301 21” Push H. D. W/O Catcher 6302 21” Push H. D. W/O Catcher 8402 21” S. P. W/O Catcher 8403 21” S. P. W/O Catcher

OTHER 7088JP 21” Push BBC W/O Bag (JCP) 8352JP 21” S. P. BBC W/O Bag (JCP)

REVISED 1983

CPSC Compliance System Chart

1983 Model 1984 Blade Brake Clutch

SUPREME 7270 21” Push with Side Catcher 7270AE 21” Push with Side Catcher, El. St.

7271 X

7231 21” Push W/O Catcher 7271AE

R8241AE R8240AE 21” S.P. with Rear Catcher, El. St. 8241AE 8240AE 21” S.P. with Side Catcher, El. St.

R8241 X R8240 21” S.P. with Rear Catcher 8241 X 8240 21” S.P. with Side Catcher

R7271 X R7270 21” Push with Rear Catcher 7232 X

4600 20” Push with Rear Catcher

8291 X 8290 21” S.P. W/O Catcher

5253 5249 19” Push W/O Catcher ~-

4600

R7270AE 21” Push with Rear Catcher, El. St. R7271AE

20” S.P. Rear Discharge 8125

MULCH-R-CATCH 4573 21” Push with Rear Catcher 8673 21” S.P. with Rear Catcher 8674 8673AE 21” S.P. with Rear Catcher, El. St.

SCAMP 4505 20” Push W/O Catcher 4506 8605 20” S.P. W/O Catcher 8606 4250 20” Push with Rear Catcher 4251

COMMERCIAL 6261 21” Push W/O Catcher 6301 21” Push H.D. W/O Catcher 6302 8402 21” S.P. W/ Catcher 8403 X OTHER 7088JP 21” Push BBC W/O Bag (JCP) 4505(JCP) 8352JP 21” S.P. BBC W/O Bag (JCP) 425O(JCP)

8072(JCP) 7072(JCP)

Flywheel Brake

PRS ZONE

X I

X X X

X

X X

I

x--

Mower Weight Specifications

Model Est. Shipping Wt. Curb Wt. 4573 81 Ibs. 4600 83 Ibs. 69 Ibs. 5249 66 Ibs. 52 Ibs. 6261 93 Ibs. 75 Ibs. 6301 82 Ibs. 65 Ibs. 7231 80 Ibs. 66 Ibs. 7270 84 Ibs. 71 Ibs.

R7270 87 Ibs. 72 Ibs. 7270AE 80 Ibs. 64 Ibs.

R7270AE 84 Ibs. 65 Ibs. 8240 94 Ibs. 77 Ibs.

R8240 97 Ibs. 78 Ibs. 8240AE 90 Ibs. 73 Ibs.

R8240AE 93 Ibs. 74 Ibs. 8290 90 Ibs. 72 Ibs. 8402 100 Ibs. 81 Ibs. 8673 93 Ibs. 79 Ibs. 8673AE 101 Ibs. 84 Ibs. 19-2 SERVICE BULLETIN REFERENCE!

69 Ibs.

Blade Brake Clutch (BBC) System

Figure 1A Brake Cable Assembly

Figure 1 B System Components (above deck) 1. Return Spring 2. Actuator Arm 3. Clevis 4. Shoulder Bolt 5 . Brake Cable 6. Spring Box 7. Spring Box Mounting Screw

Figure 2 Clutch/Brake Unit Components

1. Clutch/ Brake Housing 2. Clutch Brake Assembly 3. Actuator & Arm Assembly 4. Brake Plate 5 . Actuator Shield 6. Actuator Bearing Assembly 7. Shoulder Screws (3) 8. Socket Head Screw, Washer & Lockwasher 9. Pressure Springs (3)

..Clutch/,Brake Removal

STEP #1 (above deck) Remove the Clevis from the Actuator Arm, then use a section of starter rope (Fig. 3) to disconnect the Return Spring.


Figure 5 Figure 3 Removing Return Spring

STEP #2 Install a Piston Stop, then position the mower to allow work below the deck. Remove the 2 Blade Retaining Bolts and the Blade. Remove the 3 Muffler Retaining Bolts and the Muffler.

NOTE: An O-ring seal is used between the muffler and exhaust ports. Remove and discard this item (to be replaced with a new part during reassembly).

1. Socket Head Screw ‘2. Lockwasher 3 Flatwasher (with shoulder)

Figure 6 STEP #4 Use the Lawn-Boy Puller shown in Fig. 7 to remove the ClutchlBrake Assembly from the crankshaft. Remove the crankshaft key. NOTE: Assemble the two pulling screws into clutch at an equal depth of approximately 112” to prevent damage.

Figure 4

1. Muffler 2. Muffler Retaining Bolts 3. Blade Retaining Bolts

STEP #3 Remove the Socket Head Screw, Lockwasher and Flatwasher shown in Fig. 5. Install the Clutch Re- taining Tool shown in Fig. 6 into end of crankshaft.

19.8 REVISED

Figure 7 Clutch Retaining Tool SAFETY WARNING: The Clutch/ Brake Assembly is under 150 Ibs. tension. DO not attempt to remove it without using the Clutch Retaining Tool.

SERVICE BULLETIN REFERENCES NED 1983

NOTE: If the Clutch/ Brake Assembly

like the one shown in Fig. 8 to remove the remaining portion. separates during removal use a puller

Figure 8 Recommended Puller (example)

Snap-On Puller #CG-243-3 (shown) or Owatonna Puller #STD-80 Available from OTC Service Tool Div. Owatonna.

NOTE: Socket Head Screw must be

installing puller to prevent damage to inserted into crankshaft end before

threads inside shaft.

STEP #5 Remove the 3 Shoulder Screws and Pressure Springs, then remove the Brake Plate (Fig. 9).

Figure 9 Shoulder Screw & Spring Removal

1. Brake Plate

STEP #6 Remove the Actuator Bearing Assembly (Fig. 10).

SERVICE BULLETIN REFERENCES REV

Figure 10 Actuator Bearing Assembly

STEP #7 Remove the Actuator & Arm Assembly. This will permit removal of the ClutchlBrake Housing. Remove the Actuator Shield.

Figure 11

NOTE It may be necessary to use a puller to remove the Actuator & Arm Assembly. Illustrated above is an OTC- STD-80 Puller.

Clutch/ Brake Re-assembly and Installation

Pre-assembly Inspection

Carefully inspect all components for signs of damage or excessive wear.

NOTE: Most problems with excessive facing wear are caused by improper operation (slow engagement) or a loose or misadjusted cable.

SAFETY WARNING: Clutch/Brake Unit must be replaced if bonded facing wears to .030” or less (see following illustration).

REVISED 1983 19-9

Occasionally the actuator arm and bearing assembly will not slide onto the crankshaft easily. If not use a 3/4”-12 point deep socket and a soft hammer to install it. See Figure 12(A).

NOTE: ClutchlBrake Unit components (except fastening hardware) are not available as service items. If any

or i f the ClutchI/Brake Assembly was separated during disassembly, the entire ClutchlBrake Unit must be replaced.

Clean and inspect crankshaft. Use polishing paper to prepare crankshaft for Clutch/ Brake Unit installation.

Installation Procedure

part or parts are unsuitable for re-use

SAFETY WARNING: Apply Loctite #271 (L-B PN 388517) to all clutch/ brake hardware during assembly.

STEP #1 Pre-assemble the Actuator & Arm into the Clutch/ Brake Housing, then position the Actuator Shield onto the Arm as shown in Fig. 12.

Figure 12 ClutchlBrake Unit Pre-assembly 1. Actuator & Arm Assembly 2. Actuator Shield 3. ClutchlBrake Housing

Fit the assembly onto the engine with the Actuator Arm through the Engine Mounting Plate as shown in Fig. 13. 19-10 REVIS

Figure 13 Correct Actuator Arm Location

STEP #3 Install the ‘Actuator Bearing & Retainer Assembly and the Brake Plate.

NOTE: Arrow on Brake Plate must point toward exhaust ports (Fig. 14).

Figure 14 Shoulder Screw & Spring Installation

STEP #4 Install the’ 3 Shoulder Screws and Pressure Springs. Tighten to 13 ft. Ibs. (160 in. Ibs.).

REVISED 1983; SERVICE BULLETIN REFERENCES

STEP #5 Install the Clutch Key, then the ClutchlBrake Assembly. Secure with the Socket Head Screw, Lockwasher and Flatwasher. Tighten to 27 ft-. Ibs. (325 in. Ibs.). Be sure clutch key does not slide out.

NOTE: Be certain the Flatwasher is

toward the crankshaft. installed correctly, with the shoulder

Clutch/Brake Cable Adjustment

STEP #1 Position the Spring Box as shown so that the cable does not sag, yet isn’t too taut. Cable deflection should not exceed when light finger pressure 1/4” is applied (see Fig. 18). Tighten the Spring Box Screw to 13 ft. Ibs. (160 in. Ibs.).

Figure 16 Socket Head Screw

STEP #6 Install a new Exhaust O-ring, then attach the Muffler. Tighten the Muffler Retaining Bolts to 13 ft. Ibs. (160 in. Ibs.).

STEP #7 Attach the Blade. Tighten the Blade Retaining Bolts to 30 ft. Ibs. (360 in. Ibs.).

SAFETY WARNING: Be certain to

all fasteners beneath the mower deck. apply Loctite #271 (L-B PN 388517) to

Figure 18 Checking Brake Cable Tension

STEP #2 Test Clutch/ Brake Cable for proper adjustment by pulling bail control all the way back (against handle), then check to see that the Conduit Fitting has unseated the correct distance from the Spring Box surface, as shown in Fig. 19.

STEP #8 Move above the deck and install the Return Spring into the Actuator Arm as shown in Fig. 17.

Figure 19

Figure 17 Installing Return Spring

Clutch/ Brake Unit Testing Procedures

Braked Mode (bail control released): Connect a torque wrench to the Allen Head Screw (retaining the ClutchlBrake Assembly) and turn it in the direction of normal blade rotation. It should require at least 60 in, Ibs. torque to “slip” brake.

NOTE: Spring hook opening should face toward engine. Engaged Mode (bail control engaged, piston stop

installed): Use same procedure as described above. Torque

Reconnect the Clevis to the Actuator Arm and required to “slip” clutch should be between 50 tighten the Shoulder Bolt to 70 in. Ibs. and 60 in. Ibs.


Special Tools and Related Procedures-

In addition to the tools already mentioned, the following items are being made available to assist in BBC service:

Seal Protector This item is for use when installing a main bearing seal over the end of the new BBC crankshaft. Clean and polish crankshaft. Position the tool over the crankshaft as shown in Fig. 20. Lube the seal protector and seal, then slide the seal over the tool and into position. Use a seal driver to properly seat the seal.

NOTE: Installing the Engine Mount- ! ing Plate without this tool can cause

clutch damage or malfunction.

Position the Engine Mounting Plate and turn the Mounting Bolts partially into place. Slide the Locating Tool over the crankshaft as shown in Fig. 21. Adjust the Mounting Plate as necessary until it aligns with the tapered surface of the Locating Tool. Tighten the Mounting Bolts to 13ft. Ibs. (160 In. Ibs.). Make sure exhaust gasket is in place and aligned with the holes adjacent to exhaust ports before tightening the 2 Mounting Bolts at that location.

Figure 21 Engine Mounting Plate Alignment Tool

Figure 20 Seal Protector in place

Engine Mounting Plate Locating Tool This tool is necessary to properly align the Engine Mounting Plate on the engine of BBC models.

Special BBC Short Block Since the Blade Brake Clutch unit requires a special end on the crankshaft, a new service short block has been created. It is identical to a standard short block assembly in every respect, except for the crankshaft.

19-12 BULLETIN REFERENCES

Flywheel Brake Servicing

To service and repair the flywheel brake system, remove the shroud and tank assembly.

Figure 3 . 1

Figure 1 Remove flywheel screen. (3 screws).

Flywheel Removal / Installation It will be necessary to move the Flywheel Brake Arm away from the flywheel (pull back on control bail) to allow removalor installation of the flywheel.

Figure 2 Lift spacer from top of shroud base. (On Scamp Models only).

Figure 4

Remove flywheel nut.

To break flywheel loose use a soft hammer and rap sharply down on one of the thick fins while lifting with other hand on opposite side of flywheel.

NOTE: Do not break any fins on flywheel. It will be unbalanced and vibrate.



Pull bail back against the handle to release the brake.

Lift flywheel off.

Flywheel Configurations 1983 Flywheels are much taller than previous models. As Fig. 5 shows, the visual difference is quite apparent.

NOTE These new flywheels are not interchangeable with those of previous Lawn-Boy models.

1983 Previous Years

Figure 5 Flywheel Height Comparison

It is important to note that two different materials are used on compliance mower flywheels. Flywheels for all Flywheel Brake models are made of aluminum, but due to the need for additional rotating weight (inertia), the Blade Brake Clutch (BBC) flywheels are made of zinc. The zinc flywheels are plainly marked as such to prevent confusion. Be certain you install only the correct type flywheel for the specific mower.

Figure 6 Flywheel Brake System Components

1. 2. 3. 4. 5. 6. 7. 8. 9.

10.

Retainer Clip CUP “Pigtail” Spring Circuit Switch Switch Retaining Screw Adjusting Bolt Locknut Brake Arm Brake Arm Bolt Cable Retainer Spring

Brake Pad Wear Flywheel Brake Arm (with bonded brake pad) must be replaced if pad wears below .030” at any spot.

SAFETY WARNING: Flywheel Brake (Zone and PRS) and Blade Brake Clutch (BBC) flywheels are not interchangeable. The correct type flywheel (aluminum or zinc) is critical to proper CPSC compliance.

Figure 7 Flywheel Brake Pad Wear



To replace the brake arm, it will be necessary to Step #6 disconnect the brake cable from the engine. Thoroughly clean the threads of the bolt and ap-

ply Lawn-Boy Screw Lock, part number 384848 to

Step #7 Assemble the brake arm and bolt onto bracket.

Set the flywheel back on the engine. the threads. i

Tighten to 5-7 ft. Ibs. (63-75 in. Ibs.)

Step #8 Reassemble the cable retainer spring into the bracket assembly.

Step #9 It is necessary to check the brake cable adjustment before reinstalling it in the bracket.

Figure 8

Step #1 With flywheel in place and the bail control released (out of operating position), compress the “Pigtail” Spring by hand, then remove the Retainer Clip, Cup and Spring.

Step #2 Remove the cable from the housing.

Remove the flywheel.

Step #3 Remove circuit switch adjusting bolt and lock nut. Figure (See Fig. 6).

Step #4 Step #10 To adjust the brake cable, loosen the jam nut and

Remove brake arm bolt and brake arm. (See Fig. 6). back it off. Place the brake cable adjusting gauge,

Step #5 part number 611703 over the end of the cable. Re-assemble circuit switch adjusting bolt and lock against the gauge. Assemble the retainer clip (see fig. 9) on the cable nut into the new brake arm. Turn it into bracket until head is against the bracket. (See Fig. 6). Turn adjusting nut up against the gauge to apply

approximately 5 Ibs. tension.


Flywheel Brake Circuit Switch

Figure 12

Figure 10

Step # I1 Turn jam nut against the adjusting nut and tighten. Do not permit adjusting nut to turn.

NOTE: Use 2 1/2” open end wrenches. (See Fig. 10).

Step #12 Set flywheel back on the crankshaft.

Step #13 Reassemble the Cable into the Brake Bracket, then reassemble the Spring, Cup and Retainer Clip.

After the brake cable is reassembled, it is necessary to check the circuit switch adjustment.

Adjusting Circuit Switch

Figure 11

Step #1 Place the switch adjusting gauge Part No. 611702 on the plunger.

Step #2 Place a mark on the plunger at end of gauge. (See Fig. 12).

Step #3 Remove the gauge.

Figure 13

Step #4 Pull the bail back against the handle and hold it.

Step #5 Turn adjusting bolt in until mark on plunger is flush with face’ of switch body.

Step #6 Tighten lock nut.

NOTE Be sure adjusting bolt does not turn.

NOTE: Recheck this switch adjustment to prevent the plunger. from going in too far and damaging the switch internally. If it does not move in far enough, the engine will not start.

SAFETY WARNING: Proper adjustment of this switch is necessary to insure that blade motion stops within the required time.

NOTE: If proper switch adjustment cannot be made, check brake cable adjustment (see Fig. 9) as this will affect correct switch operation.

19-16 SERVICE BULLETIN REFERENCES 1983

Flywheel Brake Circuit Switch

Figure 14

Trouble shooting the circuit switch.

Step #1 Disconnect both leads from the C.D. pack.

Step #2 Connect a continuity meter or light to these leads.

Step #3 Push the plunger in. The meter should read “0” or the light should go out.

Figure 15

Step #5 To replace the switch, it will be necessary to remove the flywheel. This permits the brake arm to swing out of the way.

Step #6 Remove the switch retainer screw. (See Fig. 6).

Step #4 Release the plunger. The meter should indicate a completed circuit or the light will go on.

If the switch is defective, it requires replacement.


Flywheel Brake Circuit Switch I

Step #7 Using a drift punch and hammer, drive the switch body out of the bracket. (See Fig. 15). This will break the flange on the switch.

Step #8 Assemble the new switch and lead assembly into the bracket.

Step #9 Install the switch retainer screw. Reconnect the two leads onto the C.D. pack.

Step #10 Place a mark on the switch plunger using the gauge, part number 611702. Follow steps 1 thru 6 on page 16.


BULLETIN REFERENCES

CD Ignition Pack A new “Open-to-Run” ignition system is used on the 1983 models. The new style CD Pack can be identified by its dark grey color.

Beige Previous

& Later

Figure 16 CD Pack Comparison

NOTE: This Grey CD Pack cannot be used on previous Lawn-Boy Mowers.

CD Pack Testing

Use only the LAWN-BOY Test Spark Plug when performing the test and follow the described procedure. The spark coil can produce up to 28,000 Volts, causing pain- ful shock or possible injury. Do not contact the high tension lead while testing.

STEP #1 Disconnect the high tension lead and remove the spark plug.

STEP #2 Disconnect the two small switch leads from the CD Pack.

STEP #3 Attach the high tension lead to a Lawn-Boy Test Spark Plug. Clip the test plug solidly to the engine to provide a ground. (See Fig. 17).

SAFETY WARNING: Be certain the firing tip of the test plug is kept away from the spark plug hole in the cylinder. This prevents possible ignition of fuel vapors remaining in the engine.

Flywheel Brake Models A. Zone (manual) Start type

Pull the bail back against the mower handle (operating position) and pull the starter rope. If there is no spark at the test plug tip, CD Pack should be replaced.

B. Power Restart (PRS) type Pull bail back against mower handle (operating position). Turn Key Switch to “START” position (“crank” engine). If there is no spark at test plug tip, CD Pack should be replaced.

Ignition Testing

Proper Test Spark Plug position

Figure: 17

Setting Air Gaps (Flywheel Brake System)

When setting air gaps between the flywheel and C.D. pack and alternator, always release the flywheel brake. This removes pressure from the side of the flywheel and prevents the crankshaft from being pushed against the side of the bearing.

With the brake off, the air gap adjustment will be more accurate. A .010 air gap is required for both the C.D. pack and alternator. (See Fig. 18).

r

Figure 18


Fuel Systems

Alternator Lead Routing In order to help prevent accidental disconnection of the Alternator Leads, the wires should be gathered into the shroud base during reassembly so that there is no tension on the connections (see Fig. 27).

Figure 19 Correct Alternator Lead Routing

Carburetors

All 1983 models use a new carburetor that features a taller air vane and a larger diameter primer hose. This carburetor is easily recognized by its black col- or (see Fig. 19). Adjustments remain identical to previous years.

Large Primer

Previous Years 1983

Figure 20 Carburetor Comparison

NOTE: This carburetor is not interchangeable with previous models.

Primer System Draining

If a mower is tipped back on its handle (as shown below), fuel may run from the carburetor and settle in the lowest point of the primer line when the machine is set upright. If this occurs, remove the primer hose from the carburetor and drain the fuel. Symptoms include rich running and hot starting problems.


1983 ZONE & BBC STARTER

Removal

The Starter Retaining Screw (Fig. 36) now has a 114” Allen head.

Figure 20 Manual Starter Components

1. Starter Pulley 5 . Pinion Spring 2. Pin &Cup 6. Washer 3. Spring/Retainer 7. Retaining Ring 4. Pinion Gear

NOTE: Pinion Gear, Washer, and Retaining Ring are unchanged. This new type starter recoil unit will fit any “F” Series engine and will be supplied as the standard service replacement in the future. Figure 19 Starter Retainer Screw

LOOSEN AND BACK SCREW OUT 3 TO 4 TURNS.

PULL STARTER ASSEMBLY OUT OF CRANKCASE.

Manual Starters A newly designed manual starter assembly is used on the 1983 models. The Starter Recoil Spring is now held inside a Retainer to prevent spring escape during service.

SERVICE BULLETIN REFERENCES 19.21 REVISED 1983

1983 ZONE STARTER Manual Starting Systems

installation

STEP #1 Assemble Spring/Retainer into Cup so that Starter Spring Hook is beneath the Protective Flange (1) as shown in Fig. 21.

Figure 21 Proper Spring/Retainer Position

STEP #2 Mount the starter recoil assembly onto the engine in the correct position for the specific system, as shown in Fig. 22.

Figure 23

STEP #3 Position rope retainer at 6:OO o’clock position. Slide pinion spring around on pinion gear until prongs on pinion spring are positioned with one prong above flange and other below flange on C.D. mounting bracket. (See fig. 23). Slide starter assembly all the way in and tighten starter retaining screw. (See fig. 36).

6:OO o’clock Zone

Rope Length 90 Inches

Figure 22 Correct Mounting Positions


1983 BBC STARTER INSTALLATION

BBC Models

Rope Length 58 Inches

Figure 25

Flange

Figure 24

Position rope retainer on BBC models at 3:OO o’clock. Slide pinion spring around on pinion gear until prongs on pinion spring are positioned with one prong above flange and other below flange on C.D. mounting bracket. (See Fig. 25). Slide starter assembly all the way in and tighten starter retaining screw. (See Fig. 36).

Pre-Tensioning

Required pretension on the Starter Spring is 1 1/2 2 1/2 turns.

NOTE For Zone Start Models (those with the starter pull handle located on the mower handle), use the mark on the rope (located 58” from the inside end) as a guide rather than the end of the rope. This allows for the extra rope length necessary to reach the mower handle mount.

SERVICE BULLETIN REFERENCES 1983 19-23

1984 MANUAL STARTER ASSEMBLIES Service and Maintenance of Manual Starter Assembly.

On 1984 Lawn-Boy compliance mowers the manual starter assembly has been changed.

There is one for the zone start and 4600 models (see Fig. 26) another for the BBC models. (See Fig. 27).

The pinion spring has been changed. It is now held in place by an anchor welded to the pin and cup assembly. Previously it was held in place by positioning the prongs above and below a flange on the C.D. mounting bracket.

Figure 26

Zone start and 4600 models rope length 90 inches.

Figure 27

BBC models rope length 58 inches.

NOTE: The BBC manual starter assembly (fig. 27) will retro-fit all “F” series manual start models 1978 thru 1982. Both new starter assemblies (Figs. 26 and 27) will be service replacements on 1983 compliance mowers.

Figure 28

Unless the starter spring or rope breaks, it is not necessary to disassemble the starter only for cleaning, checking and fresh lubrication applied to the spring.

Manual Starter Servicing and Maintenance-

Figure 29

If the starter assembly is disassembled for replacement of the spring or for an inspection, the assembly should be cleaned and re-lubricated with Lawn-Boy “A” Grease.

NOTE Use caution when handling the spring and retainer cup assembly as it is possible for the spring to jump out.

19-24 .!983 . SERVICE BULLETIN REFERENCES

1984 Manual Starter Installation

Figure 30 Figure 32

On zone start models only assemble starter onto On BBC models, the rope retainer is placed at 3:OO engine with rope retainer positioned at 6:OO o'clock. o'clock. The pinion spring anchor will be at 6:OO Pinion spring anchor will be at 9:00 o'clock. o'clock.

Figure 31

On the model 4600 the rope exits through the top of the shroud. Therefore, the rope retainer must be positioned at 3:OO o'clock. Pinion spring anchor will be at 6:OO o'clock.

Electric Starter Servicing and Maintenance

An improved electric starter is supplied on 1983 models. It features larger drive gears and a newstyle mounting. See Fig. 33.

Figure 33 Electric Starter Components

1. Retaining Ring 2. Pinion Stop Washer 3. Pinion Spring 4. Pinion Gear & Spring 5. Electric Motor Assembly

Figure 34

When servicing and repairing the electric starter, always apply Lawn-Boy “A” Grease to the gears before re-assembling.

NOTE: This unit will not interchange with previous models.

Adjustment Install the unit with a .020-.030” gap where shown in Fig. 35.

19-26

Figure 35 Correct Mounting SERVICE BULLETIN REFERENCES 1983

Piston and Rod A .020” decompression hole (made by Laser beam) is now in the top of the piston to ease starting. Tests have shown no tendency for the hole to become plugged during mower operation when Lawn-Boy oil was used. If there is ever a need to clean the hole, be certain not to use a tool larger than .020”, as this will reduce compression and engine efficiency.

Minimum allowable compression for engines with this piston is 80 PSI.

NOTE: This new piston will become

all “F” Series engines. (See Fig. 36). the standard service replacement for

The connecting rod cap has been reinforced for added strength and 5/32” Allen-head capscrews are now used. These screws are now coated with a special epoxy resin. Torque specifications remain the same at 60 in. Ibs. (tightened in 20 in. Ib. increments). Lock plates are no longer used.

Figure 37 New Piston and Rod

NOTE: If screws are reused, be sure to clean the threads thoroughly and apply OMC Ultra Lock, part number 388517, or Loctite #271, before assembly.


Blade and Blade Housing

Figure 38

Assemble muffler onto crankshaft.

Figure 40

A special, tool, crankshaft support gauge, part number 609968 is required to position the support correctly so it doesn’t contact the crankshaft.

Slide the gauge onto crankshaft with the thin wall of gauge Inside of support.

Figure 39

Always assemble the crankshaft support with the flange down towards the blade.

Figure 41

Clean threads on muffler bolts thoroughly and apply Ultra-Lock, part number 388517. Install bolts and tighten to 150-190 inch pounds.


Blade and Blade Housing

The Blade and Hardware shown below are used on all Lawn-Boy Scamp models.

Figure 42

Torque blade nut to 45-50 ft Ibs.

NOTE: This Blade and Hardware will fit all previous Lawn-Boy mowers, using only the Blade Driver and Blade Nut (as shown in Fig. 42). Do not use the old blade stiffener or washer with these new blades.

Figure 43


If the blade nut is to be re-used, clean the threads thoroughly. Also clean threads on crankshaft.

Apply QMC Ultra-Lock, part number 388517 on the threads. Torque blade nut to 45-50 foot pounds.

NOTE: After repairs are completed always test the mower for starting, running and blade stoppage time.

The required blade stopping time ,is 3 seconds or less.

It is recommended to make 3 tests for blade stopping time and record each for future reference.

If it doesn’t stop in the required length of time, determine what the problem is and correct it.


Hose and Wire Routing It is important to correctly route and secure all hoses and wires when reassembling mower components after servicing. The following reference photos show typical examples of correct routing and tie locations:

BBC Models

Control Console

Retainer Cup Removal

Tie Wrap Locations 1. Single Tie 2. Double Tie

-Hose and Cable Routing

1. Tie Wrap 2. Electrical Cable Connector 3. Brake Cable 4. Primer Hose

Primer and Switch Assemblies 5. Electrical Cable


Power Restart (PRS) Models

Control Console



Hose and Cable Routing 1. Tie Wrap 4. Brake Cable Retainer Clip 2. Primer Hose 5. Electrical Cable 3. Brake Cable 6. Switch Lead Retainer Clip

For Your Information The following service items are passed along as general information and do not necessarily apply only to new models. Vented Bowl Carburetors (identify by noting the vent hole in the primer bulb) must have a drop of Lawn-Boy Nut and Screw Lock applied to the threads of high-speed nozzle prior to carburetor assembly. 8” Wheels now include an oil-impregnated bronze bearing (non-removable).

Primer and Switch Assemblies

SERVICE BULLETIN REFERENCES .19-33 1983

Zone Start Models



Primer Assembly

Brake Cable Routing (console)

Hose and Cable Routing

1. Primer Hose 2. Brake Cable 3. Brake Cable Retainer Clamp 4. Switch Cable Clamp


I)

a

J


1983

TROUBLE SHOOTING

Engine Won’t Start or Hard Starting ALL MODELS

Possible Cause No fuel in tank. Fuel valve off. Insufficient or excessive priming. Spark plug lead disconnected. Spark plug fouled. Low compression in cylinder (80 PSI min.) Incorrect air gap between C.D. pack and flywheel. C.D. pack defective. (Refer to “CD Pack Testing,” Pg. 19) Primer hose disconnected from carburetor or connector. Primer hose restricted. (Refer to “Primer System Draining,” Pg. 20). Air filter restricted. Carburetor needle valve incorrectly adjusted. Throttle valve stuck closed. Carburetor-to crankcase screws not tight. Carburetor-to crankcase gasket leaking air. Float chamber screws loose. Float chamber gasket leaking air. Restriction in high speed nozzle. High speed nozzle loose. Float valve stuck closed. Restriction in fuel passages (tank, valve, hose, float valve seat). Float level set too low. Reed Valves stuck closed or bent open more than .015”. Air leak between crankcase halves. Intake plug leaking or missing. Main bearing seals leaking. Exhaust system restricted. Zone Start Models Bail not pulled back against handle. Incorrect kill switch adjustment (see Fig. 16). Kill switch inoperative. (See “Ignition Circuit Switch Troubleshooting,” Pg. 17). Brake dragging on flywheel. Power Restart (PRS) Models Bail not pulled back against handle. Incorrect kill switch adjustment (see Fig. 16). Kill switch inoperative. (See “Ignition Circuit Switch Troubleshooting,” Pg. 17). Brake dragging on flywheel. Battery disconnected. Battery run down (should be 12.5 14 volts). Starter motor cable disconnected. Starter solenoid defective. Key switch and cable connect disconnected or loose from engine harness. Key switch defective or loose connectors. BBC Models Switch turned off. Switch defective or loose connectors.

Ignition circuit (“Kill”) Switch (Zone & ‘PRS Models) The following conditions are indications of Switch misadjustment or failure.

Engine misfires when in self-propelling mode Adjust Switch (See Fig. 16)

Engine stops i f bail is not held extremely tight against handle

Adjust Switch (See Fig. 16) ,

Engine won’t start (no spark) Adjust or replace switch

Primer System Draining If a mower is tipped back on its handle (as shown below), fuel may run from the carburetor and settle in the lowest point of the primer line when the mach,ine is set upright. If this occurs, remove the primer hose from the carburetor and drain the fuel. Symptoms include rich running and hot starting problems.


Wire Routing Diagram

Power Restart (PRS)

A ( Battery

To Handle

SERVICE BULLETIN REFERENCES. ............................................................................................................. 19-37 REVISED 1983

Trouble Shooting And Test Procedures To Be Followed In Sequence Below

(For Plug And Switch References See Page 19-22)

A. Starter will not turn engine (1st check) 1. Bail not pulled back against handle

completely.

2. Key Switch not actuated or not functioning.

3. Plugs A-B-C- or E not connected.

4. Brake Switch (G) not actuated or not functioning.

5. Low charge in battery.

B. Starter will not turn engine (2nd check) 1. Disconnect plug (C) from battery.

2. Connect volt-ohm-meter (VOM) across plug ((2-2).

3. Meter should indicate.

High Resistance

To Engine Low Resistance OHMS ± 10 MIN.

4. If the meter does not indicate the correct reading on the resistance scale,

a. See alternator test procedures pages 13-19 & 13-20.

5. Connect meter (vom) as illustrated in step (3-A).

6. Pull bail back against handle.

7. Turn switch key.

9. If there is no reading on the meter, proceed as follows otherwise i f there is a reading on the meter, proceed to step (14).

10. With no reading on step (9) Disconnect plug (a), connect a jumper lead across plug (A-2) shorting terminals to each other.

11. Pull bail back against handle. If meter indicates 80 ohms ± 15, the key switch is defective.

8. Meter should indicate

80 ohms ± 15 on low resistance scale


12. Remove jumper lead from (A-2). Connect the jumper lead between terminals (4 and 3) on plug (B-2). See below.

PLUG (B-2)

JUMPER LEAD

REAR VIEW

13. If meter indicates 80 ohms ± 15, the brake (kill) switch is defective or requires read- justment. If the meter does not indicate 80 ohms ± 15, the solenoid relay is defective and requires replacement.

14. Connect jumper lead across terminals (4 and 2) on plug (B-2)

JUMPER LEAD

PLUG (B-2)

REAR VIEW

15. If meter indicates 3 ohms 2.5, replace solenoid relay. If meter does not indicate 3 ohms ± 2.5, the starter assembly requires replacement.


Zone (manual) Start

Tubing


4250, 4505, 8605 AND LATER COMPLIANT MOWERS

All Lawn Boy Compliant Scamp Model Mowers feature a Flywheel Brake system. It will stop the blade from turning within 3 seconds after the operator releases the bail. The engine also stops at the same time.

Adjustments and servicing of the Scamp self- propelled mowers are very different from all previous models of self-propelled mowers.

SAFETY WARNING: Before any adjustments or repairs are attempted, disconnect and remove spark plug to prevent starting.



2. Align hole in clip with hole in arm and assemble lower end of the control rod in hole.


SCAMP MODELS

SERVICING AND ADJUSTMENTS SELF-PROPELLED

SAFETY WARNING: The lower self- propel control rod must be assembled to clutch arm as shown. If not the self- propel mechanism will not return to neutral when the control lever is released from the engaged position.

SCAMP MODELS SELF PROPELLED SERVICING AND ADJUSTMENTS

4. With the control handle in “neutral” (free) posi- 6. Secure upper and lower control rods together tion as shown. with the clamp screw as shown. This screw should

be tightened securely by hand.


SAFETY WARNING: Improper tightening of clamp screw on control rod may result in operator loss of drive control mechanism.

NOTE: To put mower in motion, pull upward on control handle and hold in drive position. To stop forward motion of mower, release control handle. Mower drive mechanism functions only when the control handle is held in “DRIVE” position.

19.42 SERVICE BULLETIN REFERENCES 1983

SCAMP MODELS SELF PROPELLED

SERVICING AND ADJUSTMENTS


1. With the control handle in “Neutral”, place both 2. Loosen bolt and nut located in drive roller gap rear wheel height adjusters in #1 (lowest) cutting adjusting slot on each side of drive roller bracket. position as shown. A gap of 3/16” should appear between the drive rollers and tires. 3. Move the drive roller bracket up or down to ob-

tain the necessary 3/16’’ drive roller gap. Hold bracket in position and tighten both bolts and nuts securely.

SCAMP MODELS

REPLACEMENT AND SERVICING SELF-PROPELLED DRIVE BELT


SAFETY WARNING: To prevent starting engine, disconnect spark plug lead and remove spark plug.

The “V” belt used on the utility self-propelled model mowers is a SPECIAL BELT. DO NOT USE A SUBSTITUTE. It won’t work as WELL or as LONG.

To remove the belt:


2. Turn mower up on side and remove nut, blade and collar. Remove three bolts securing muffler and crankshaft support. Remove muffler.


6. Remove belt from driven pulley and slide shaft assembly to the right. Remove belt from mower as shown.

SCAMP MODELS


SAFETY WARNING: To prevent starting of engine, disconnect and remove spark plug prior to removing the engine.


NOTE: Do not remove muffler plate from housing when removing engine.


SAFETY WARNING: Do not operate mower with belt guard removed.


SCAMP MODELS


NOTE: After the belt has been removed, examine for broken, cracked or misaligned pulleys. The condition and the wear pattern of the belt will provide clues for the above possibilities. Replace damaged or worn pulleys.

7. The crankshaft pulley (drive pulley) is secured to the crankshaft with a SPECIAL slotted set screw. The end of this screw locates in a hole in the crankshaft. The correct position and tightness is very IMPORTANT. If not tightened securely, damage to the pulley, crankshaft and premature wear of the drive belt will result.

NOTE: Apply OMC Ultra-Lock Part No. 388517 to threads of set screw prior to installation.

8. When reinstalling pulley to crankshaft, the side of the pulley with set screw is the lower side. If assembled upside down (set screw on top) misalignment and interference of pulley operation will result. Always check pulley for damage. Replace i f necessary.


IDLER PULLEYS TOP STRAND

1 DRIVE- BOTTOM STRAND ENGINE SHAFT DRIVE PULLEY PULLEY

SCAMP MODELS


SAFETY WARNING

SAFETY WARNING: Incorrect drive belt installation may allow mower to operate in reverse direction causing injury to the operator or bystanders. Assemble drive belt as shown.


11. Check the condition of the drive shaft, bronze bearings, and sleeve. If signs of damage or wear appear, replace them.

SERVICE BULLETIN REFERENCES ................................................................................................................................................................... 19.47 1983

SCAMP MODELS





14. Using a new roll pin, assemble the drive roller to the drive shaft. Use a 5/32” or larger drift punch, drive the roll pin into place, flush with the outer surface. Neither end should protrude beyond the roller surface.

15. As you face the front of the mower, twist the forward end of the belt 1/4 turn counter clockwise and assemble on the engine drive pulley. Assem- ble engine on muffler plate and secure with three bolts.

16. Release spring tension on idler pulleys and assemble belt on drive shaft pulley. Reassemble idler pulley spring and rotate the belt several revolutions. Check to make sure the belt is centered on the’ pulleys and TURNING IN RIGHT DIRECTION. Note direction of arrow on large pulley in illustration above. Check and adjust belt tension i f necessary. Refer to BELT TENSION ADJUSTMENT.

NOTE When replacing either of the. belt idler assemblies, use idler kit part no. 682374 for the top and kit part no. 682564 on the bottom.

19-48 .... 1983 SERVICE BULLETIN REFERENCES

2. Drive belt should be checked to insure that proper tension exists in order to prevent premature belt failure. Lift floating idler from the upper strand of “V” belt. Belt will then become loose. Set floating idler onto “V” belt and check clearance between the two strands of the “V” belt. The distance between the two strands should not be less than 112” as shown.

complished by measuring the distance from the front edge on the height adjuster brackets to the 1/4” diameter gage holes located directly in front of these brackets as shown. This distance must be the same for both sides. Before tightening screws make sure the distance between the strands of the “V” belt is not less than 112”. Tighten the four handle bracket screws and the two side screws securely. Reassemble belt guard to self-propel mechanism using screws previously removed.’

SAFETY WARNING SAFETY WARNING: Do not operate mower with belt guard removed.


SCAMP MODELS


LUBRICATION

50 HOURS

1. DRIVE ROLLER BEARINGS-Disassemble rotating shaft cover from self-propel mechanism by removing four screws. Unscrew plug from end of each drive roller (Point “A”). Fill exposed cavity with

EQUIVALENT. Replace plug and tighten until snug. Repeat procedure until lubricant appears on cross- shaft at Point “B”. Reassemble rotating shaft cover to self-propel assembly.

LAWN-BOY “A” GREASE, PART NO. 610726 OR

FOUR PLACES

BOLT-PULLEY-ARM-NUT LOWER IDLER ASSEMBLY

PART #682564

LOWER IDLER PULLEY-Permanently lubricated. No lubrication required.

FLOATING IDLER PULLEY-Do not immerse the idler pulley in solvent. Use a rag containing solvent, clean the hole in the idler pulley and the shoulder bolt thoroughly. Using a small amount of LAWN- BOY “A” GREASE or EQUIVALENT, relubricate the shoulder bolt and remount idler pulley assembly in the same order i t was originally.

AS REQUIRED

1. CLUTCH LINKAGE-Apply several drops of light machine oil on clutch mechanism at all pivoting points.

19.50 ...........................SERVICE BULLETIN REFERENCES 1983

SCAMP BRAKE SERVICING

AND REPAIR

To service and repair the flywheel brake system, remove the shroud and tank assembly. (5 Phillips screws).

Figure 1

Figure 2

Lift spacer from top of shroud base.

Figure, 3

Remove flywheel screen. (3 screws).

Flywheel Removal/Installation It will be necessary to move the Flywheel Brake Arm away from the flywheel (pull back on control bail) to allow removal or installation of the flywheel.

Figure 4

Remove flywheel nut.

To break flywheel loose use a soft hammer and rap sharply down on one of the thick fins while lifting with other hand on opposite side of flywheel.

NOTE: Do not break any fins on flywheel. It will be unbalanced and vibrate.


SCAMP BRAKE SERVICING AND REPAIR

Pull bail back against the handle to release the brake.

Lift flywheel off.

Flywheel Configurations 1983 Flywheels are much taller than previous models. As Fig. 5 shows, the visual difference is quite apparent.

NOTE These new flywheels are not interchangeable with those of previous Lawn-Boy models.

1983 Previous Years

Figure 5 Flywheel Height Comparison

It is important to note that two different materials are used on compliance mower flywheels. Flywheels for all Flywheel Brake models are made of aluminum, but due to the need for additional rotating weight (inertia), the Blade Brake Clutch (BBC) flywheels are made of zinc. The zinc flywheels are plainly marked as such to prevent confusion. Be certain you install only the correct type flywheel for the specific mower.

SAFETY WARNING: Flywheel Brake (Zone and PRS) and Blade Brake Clutch (BBC) flywheels are not interchangeable. The correct type flywheel (aluminum or zinc) is critical to proper CPSC compliance.

Figure 6 .Flywheel Brake System Components

1. Retainer Clip 2. cup 3. “Pigtail” Spring 4. Circuit Switch 5. Switch Retaining Screw 6. Adjusting Bolt 7. Locknut 8. Brake Arm 9. Brake Arm Bolt

10. Cable Retainer Spring

Brake Pad Wear- Flywheel Brake Arm (with bonded brake pad) must be replaced i f pad wears below .030” at any spot.

.030” Minimum

Figure 7 Flywheel Brake Pad Wear


SCAMP BRAKE

SERVICING AND REPAIR To replace the brake arm, it will be necessary to STEP #6 disconnect the brake cable from the engine. Thoroughly clean the threads of the bolt and apply

Lawn-Boy Screw Lock, part number 384848 to the Set the flywheel back on the engine. threads.

Figure 8

STEP #1 With flywheel in place and the bail control released (out of operating position), compress the “Pigtail” Spring by hand, then remove the Retainer Clip, Cup and Spring.

STEP #2 Remove the cable from the housing.

Remove the flywheel.

STEP #3 Remove circuit switch adjusting bolt and lock nut. (See Fig. 6).

STEP #4 Remove brake arm bolt and brake arm. (See Fig. 6).

STEP #5 Re-assemble circuit switch adjusting bolt and lock nut into the new brake arm. Turn it into bracket until head is against the bracket. (See Fig. 6).

STEP #7 Assemble the brake arm and bolt onto bracket.

Tighten to 5-7 ft. Ibs. (63-75 in. Ibs.)

STEP #8 Reassemble the cable retainer spring into the bracket assembly.

STEP #9 It is necessary to check the brake cable adjustment before reinstalling it in the bracket.

Figure 9

STEP #10 To adjust the brake cable, loosen the jam nut and back it off. Place the brake cable adjusting gauge, part number 611703 over the end of the cable. Assemble the retainer clip (see Fig. 9) on the cable against the gauge.

Turn adjusting nut up against the gauge to apply approximately 5 Ibs. tension.


SCAMP BRAKE SERVICING AND REPAIR

STEP #2 Place a mark on the plunger at end of gauge. (See Fig. 11).

STEP #3 Remove the gauge.

Figure 10

STEP #11 Turn jam nut against the adjusting nut and tighten. Do not permit adjusting nut to turn. Figure 12

STEP #4 (See Fig. 10). Use 1/2” Open end wrenches. Pull the bail back against the handle and hold it.

STEP #12 Set flywheel back on the crankshaft.

STEP #5 Turn adjusting bolt in until mark on plunger is flush with face of switch body.

STEP #13 Reassemble the Cable into the Brake Bracket, then Tighten nut. reassemble the Spring, Cup and Retainer Clip.

STEP #6

After the brake cable is reassembled, it is necessary to check the circuit switch adjustment.

NOTE Be sure adjusting bolt does not turn.

NOTE Recheck this switch adjustment to prevent the plunger from going in too far and damaging the switch internally. If it does not move in far enough, the engine will not start.


NOTE If proper switch adjustment cannot be made, check brake cable adjustment (See Fig. 9) as this will affect correct switch operation.

Figure 11

STEP #1 Place the switch adjusting gauge on the plunger.

19.54 SERVICE BULLETIN REFERENCES 1983

I SCAMP

IGNITION CIRCUIT SWITCH TESTING AND REPLACEMENT

Trouble shooting the circuit switch. STEP #7 ‘-Using a drift punch and hammer, drive the switch

STEP #1 body out of the bracket. (See Fig. 13). This will break Disconnect both leads from the C.D. pack. the flange on the switch.

STEP #2 Connect a continuity meter or light to these leads.

STEP #3 Push the plunger in. The meter should read “0” or the light should go out.

STEP #4 Release the plunger. The meter should indicate a completed circuit or the light will go on.

If the switch is defective, it requires replacement.

STEP #8 Assemble the new switch and lead assembly into the bracket.

STEP #9 Install the switch retainer screw. Reconnect the two leads onto the C.D. pack.

STEP #10 Adjust the switch plunger travel with the gauge, part number 61 1702. Follow steps 1 thru 6 on page 14.


Figure 13

STEP #5 To replace the switch, it will be necessary to remove the flywheel for access to the switch. This permits the brake arm to swing out of the way.

STEP #6 Remove the switch retainer screw. (See Fig. 6).


SCAMP BLADE AND BLADE HOUSING

Figure 1

Assemble muffler onto crankshaft.

Figure 2

Figure 3

A special tool. crankshaft support gauge, part number 609968 is required to position the support correctly do it doesn’t contact the crankshaft.

Slide the gauge onto crankshaft with the thin wall of gauge inside of support.

Always assemble the crankshaft support with the flange down towards the blade.

Figure 4

Clean threads on muffler bolts thoroughly and apply Ultra-Lbck, part number 388517. Install bolts and tighten to 150-190 inch pounds.

19-56.. SERVICE BULLETIN REFERENCES 1983

The Blade and Hardware shown below are used on all Lawn-Boy Scamp models.

Figure 5

Torque blade nut to 45-50 ft. Ibs.

NOTE: This Blade and Hardware will fit all previous Lawn-Boy mowers, using only the Blade Driver and Blade Nut (as shown in Fig. 5). Do not use the old blade stiffener or washer with these new blades.

Figure 6

SCAMP BLADE AND BLADE HOUSING


If the blade nut is to be re-used, clean the threads thoroughly. Also clean threads on crankshaft.

Apply OMC Ultra-Lock, part number 388517 on the threads. Torque blade nut to 45-50 foot pounds.

NOTE After repairs are completed always test the mower for starting, running and blade stoppage time.

The required blade stopping time is 3 seconds or less.

It is recommended to make 3 tests for blade stopping time and record each for future reference.

If it doesn't stop in the required length of time, determine what the problem is and correct it.


Zone Start Models

Brake Cable Routing (console)



Primer Assembly

19-60

Hose and Cable Routing

I. Primer Hose Brake Cable

3. Brake Cable Retainer Clamp 4. Switch Cable Clamp



Zone (manual) Start

Tubing


19-62 SER

VICE BULLETIN REFERENCES

TROUBLE SHOOTING

Engine Won’t Start or Hard Starting SCAMP

Possible Cause No fuel in tank. Fuel valve off. Insufficient or excessive priming. Spark plug lead disconnected. Spark plug fouled. Low compression in cylinder (80 PSI min.) Incorrect air gap between C.D. pack and flywheel. C.D. pack defective. (Refer to “CD Pack Testing,” Pg. 15) Primer hose disconnected from carburetor or connector. Primer hose restricted. (Refer to “Primer System Draining,” Pg. 63) Air filter restricted. Carburetor needle valve incorrectly adjusted. Throttle valve stuck closed. Carburetor-to crankcase screws not tight. Carburetor-to crankcase gasket leaking air. Float chamber screws loose. Float chamber gasket leaking air. Restriction in high speed nozzle. High speed nozzle loose. Float valve stuck closed. Restriction in fuel passages (tank, valve, hose, float valve seat). Float level set too low. Reed Valves stuck closed or bent open more than .015”. Air leak between crankcase halves. Intake plug leaking or missing. Main bearing seals leaking. Exhaust system restricted. Zone Start Models

Incorrect kill switch adjustment (See Pg. 54 Fig. 12) Kill switch inoperative. (See “Ignition Circuit Switch Troubleshooting,” Pg. 19-17). Brake dragging on flywheel.

Bail not pulled back against handle.

Ignition Circuit (“Kill”) Switch (Zone) The following conditions are indications of Switch misadjustment or failure.

Engine misfires when in self-propelling mode Adjust Switch (See Pg. 54 Fig. 17).

Engine stops if bail is not held extremely tight against handle

Adjust Switch (See Pg. 54 Fig. 17).

Engine won’t start (no spark) Adjust or replace switch

Primer System Draining If a mower is tipped back on its handle (as shown below), fuel may run from the carburetor and settle in the lowest point of the primer line when the machine is set upright. If this occurs, remove the primer hose from the carburetor and drain the fuel. Symptoms include rich running and hot starting problems.


Fig. 1

The model 8125 is new. It features rear discharge with a die cast aluminum housing and is a gear driven self-propelled mower. Fig. 1.

It is a zone start model with the flywheel brake system. When the bail is released, both the engine and blade will stop within the 3-second time limit.

Another feature is an adjustable driven pulley which controls ground speed. It is located under the pulley cover.

SAFETY WARNING:

Disconnect the spark plug lead.

Remove two screws and lift cover off. Fig. 2.

.Fig. 2

With the engine operating at 3200 rpm, the ground speed can be controlled to operate at 2.4, 2.6, 2.8, 3.0 or 3.2 mph.

MODEL 8125 SERVICING AND REPAIR

CHANGING GROUND SPEED.

Fig. 3

Loosen the nu t on the idler pulley bracket which will release the tension on the belt. Remove the nut and thick washer from the top of the driven pulley. When a spacer or spacers are not used, they are stored on top of the pulley under the nut and washer. Fig. 4.

Fig. 4

SERVICE BULLETIN REFERENCES 20-1 OCTOBER 1984

With no spacers between the pulley halves, the ground speed is 2.4 mph at 3200 rpm. Add one spacer between the pulley halves, the speed increases to 2.6 mph. Two spacers 2.8 mph. Three spacers 3.0 mph. Four spacers 3.2 mph.

Fig. 5

The lower half of the pulley is keyed to the driven shaft in the transmission. Fig. 6.

After the ground speed has been selected, assemble the top half of the pulley onto the shaft. Fig. 7.

Fig. 7

Slide the pulley down making sure the two halves are assembled correctly. Fig. 8.

Fig. 6

Fig. 8

Place the extra spacers on top of the pulley, assemble the washer and nut. Tighten the nut. Fig. 9.

Fig. 9

20-2 SERVICE BULLETIN REFERENCES OCTOBER 1984

Move the idler bracket to apply tension on belt and tighten idler bracket nut. Fig. 10-A. Belt should deflect approximately 3/8” with firm finger pressure. Fig. 10-B. Rotate engine several times to seat belt in grooves. Recheck belt tension and adjust as necessary.

To replace the belt, remove the pulley cover. Loosen the nut on the idler pulley bracket which will release tension on the belt. Fig. 12.

At this time, the belt can be rolled off the driven pulley, or you can separate the pulley to remove it.

Fig. 10-A Fig. 10-B

BELT REPLACEMENT PROCEDURES

A special belt is used to drive the transmission. It was specially designed and manufactured for use only on this mower.

NOTE:

Use only the belt available from Lawn-Boy No other belt will function properly on this mower.

SAFETY WARNING:


Fig. 12

It is necessary to remove the engine when replacing the belt.

Remove the blade nut, blade and collar. Remove three screws securing muffler and crankshaft support. Remove muffler. Fig. 13.

Fig. 13

Fig. 11

SERVICE BULLETIN REFERENCES.. 20-3 OCTOBER 1984

Remove the four bolts that retain the engine to the Install a new exhaust gasket. Fig. 16. muffler plate. Fig. 14.

NOTE:

Hold the engine while removing these bolts. Don’t let it drop.

Fig. 16

Place the new belt over the drive pulley and set engine back onto the muffler plate. Fig. 17.

Fig. 14 Don’t disturb the new exhaust gasket when putting

Lift the engine up and remove the old belt. Also remove the old exhaust gasket and dispose of it.

the engine in place.

Fig. 17 Fig. 15

Block one side of mower up. Fig. 18. Clean the threads of the engine mounting bolts with LOC Quic Primer, Part #384884. Apply OMC Ultra Lock, Part #388517 to the threads of the bolts and assemble all four into the engine mounting holes.

Clean the threads of the three muffler screws with LOC Quic Primer, Part #385884. Apply OMC Ultra Lock, Part #388517 to the threads.

Assemble the muffler, crankshaft support (flange down) and start the three screws.

Fig. 18 Fig. 20

Tighten all four engine mounting bolts to 150-190 in. Ibs. (11-15 ft. Ibs.) Slide crankshaft support gauge, Part #609968 over

the crankshaft with the thin wall of gauge going between the support and crankshaft. Fig. 21.

Fig. 19

Fig. 21


Tighten all three screws to 142-170 in. Ibs., 12-14 ft. Ibs. Fig. 22.

Fig. 22

Assemble the collar, blade and nut onto crankshaft. Tighten blade nut to 45-50 ft. Ibs.

NOTE:

If the blade nut has been on and off four times it should be replaced. If not replaced, apply OMC Ultra Lock to threads of crankshaft before installing nut.

SAFETY WARNING:

Check the torque of all fasteners under the deck. for tightness. A loose fastener can become a .thrown object.

Assemble the belt on the drive pulley of the cranksha’ft. With the idler pulley bracket loose, the belt should assemble over the driven pulley very easily. Fig. 24.

Fig. 24

Move the idler pulleys to apply tension on belt. Cor- rect tension will be approximately 3/8” deflection with firm finger pressure. Fig. 25. Rotate engine several times to seat belt in grooves. Recheck belt tension and adjust as necessary.

After completing the belt replacement, start and run the mower to check operation of the drive system.

Fig. 25

Fig. 23


Fig. 27 Fig. 29

BULLETIN REFERENCES 20.7 OCTOBER 1984

To prevent dirt from entering inside of the wheel, apply Lawn-Boy “A” grease in the groove of the wheel cover. Fig. 30.

The transmission assembly is filled with “A” grease at the factory and should not require additional lubrication. However, if seepage of the lubricant is noted coming from around the seals or from the transmission housing gasket area (Fig. 32-A), grease can be added through the zerk fitting located on, the lower side of the transmission. Fig. 32-6.

Fig. 30

Every 50 hours of operation the rear wheel bolts should be lubricated. Remove and clean the wheel bolt, liberally oil the bearing and each felt washer and reassemble. Fig. 31.

Fig. 32-A Fig. 32-6

Should it be necessary to add lubricant to transmission, watch for an upward movement of the clutch arm when putting grease in. When movement is noted, stop the flow of lubricant immediately. Fig. 33.

NOTE:

Do not put an excessive amount in transmission because there is a possibility of a pressure build- up resulting in seal failures.

Fig. 33

20-8 ................................................................................................................................................................... SERVICE BULLETIN REFERENCES OCTOBER 1984

FRONT WHEEL MAINTENANCE

It is not necessary to lubricate the front wheel bolts.

For engine, exhaust and blade servicing refer to their respective sections in the Manual.

TRANSMISSION SERVICING AND REPAIR

WARNING:


Remove the hairpin retainers and detach the handle from the brackets. Lay the handle down over front of mower. Fig. 34.

Remove the driven pulley assembly from the transmission. Fig. 36.

Fig. 36

Remove the 7/16” nut from long transmission bolt that retains the clutch cable bracket and spring assembly to transmission. Lift the bracket, springs and arm assembly off transmission. Lay to one side.

Fig. 34

Remove two screws and lift cover off. Fig. 35.

Fig. 37

.Fig. 35


An “0” ring is preassembled on the hub of the clutch arm before final assembly. When removing the arm from the transmission, the “0” ring slides off into the hole and around the square shaft of the shift fork. It will have to be removed from the hole. Fig. 38.

Remove the right rear wheel bolt with a 314” socket.

Fig. 38

To free the transmission from the housing, remove the shoulder bolt and nut. Fig. 39.

Fig. 39

Fig. 40

Using a pair of expansion pliers, remove the retaining ring from end of shaft. Fig. 41.

Fig. 41

The pinion gear is driven with a spring loaded key located in the shaft. Before removing the gear, turn it in both directions. It turns forward freely with a clicking or ratcheting noise. This noise is created by the key dropping over the driving shoulder of the gear. Turn backward and the shoulder of the gear moves up against the key which provides the self- propelling. This will be found on both rear wheels.

Fig. 42

When removing the gear from the shaft, be very careful because the key, being spring loaded, can pop out and be lost. The spring also can become lost. Fig. 43.

Fig. 43

Behind the pinion gear is another retaining ring. Remove it and slide the wheel cover off. Remove the left wheel, pinion gear and wheel cover. Fig. 44.


Push the bronze bearing and retainers out of the bracket. Check the bearing surfaces for damage and wear. Replace if necessary. Also note the six lubricating holes in the bracket hub. When grease flows in, it follows a passage around the hub and out of each hole into the two holes in the bronze bearing and lubricates the shaft. Fig. 46.

Carefully pull the transmission and shaft assembly out of the ‘left hand bracket. Fig. 48.

Fig. 48

Unless there is leakage from around the seals or gasket, or a failure internally, it will not have to be disassembled.

Fig. 46

The plastic bearing retainers are in two halves. One half has a lug or tab that locates in the recess of the other half. The slots permit lubrication to flow into the holes of the bronze bearing.

NOTE:

The bearing and plastic retainer assembly may be installed in bracket hub as removed or reversed. Either way is correct. Fig. 47.

Fig. 49

1. Input Shaft 2. Driveshaft 3. Trans. Mounting Bolt Hole 4. Control Cable Mounting Bolt 5. Seals 6. Shift Fork

Fig. 47

20-12 ................................................................................................................................................................. SERVICE BULLETIN REFERENCES OCTOBER 1984

Remo’ve the input (worm) shaft assembly.

Fig. 50

1. Packing 2. Input Shaft & Bearing 3. Worm Wheel 4. “0” Ring Retainer 5. Shift Collar 6. Shift Fork 7. Driver Assembly 8. Bearing & Seal Assembly Fig. 51

and bearing

Fig. 52

1. Bearing & Seal Assembly 10. Driven Plates (7) 2. Thrust Race (Thin) 11. Driven Sleeve 3. Thrust Bearing 12. Pin 4. Thrust Race (Thick) 13. Shift Collar 5. Washer (Worm Wheel) 14. Shift Fork 6. Worm Wheel 15. “0” Ring Retainer 7. Snap Ring 16. Transmission Packing 8. Driver 17. Transmission Gasket 9. Driver Plates

SERVICE BULLETIN REFERENCES ................................................................................................................................................................. 20-13 OCTOBER 1984

Wash and clean all parts. Inspect for wear or damage. Replace any worn or damaged parts.

If either the worm or worm wheel are worn or damaged (Fig. 52), always replace both at same time. Also, i f one or more of the driver plates or driven plates are worn or damaged, replace all of them.

Whenever complete disassembly of the transmission is necessary, replace both packings and gasket (Fig. 52).

Correct sequence in reassembly of the driver and driven plates into the housing is very important. If reassembled incorrectly, the transmission will not function properly. There are six driver plates (Ref. 2) and seven driven plates (Ref. 3, Fig. 54). Starting with a driven plate, place it in the housing. Next, assemble a driver plate, then a driven and continue alternating with every other one being a driver plate and the last one being a driven plate. Assemble the driven sleeve (Ref. 4, Fig. 54) into the plates, turning so it will go all the way down. If it has engaged all of the driven plates, it will be fully seated.

Fig. 54

Fig. 53 1. Driver 2. Driver Plate 3. Driven Plate 4. Driven Sleeve

The clutch assembly will locate between the pin hole and snap ring groove in the shaft. Fig. 55. The spline end of driver housing will locate next to the groove with the slotted end of the driven sleeve being positioned over the pin hole.

Fig. 55

20-14 ................................................................................................................................................................. SERVICE BULLETIN REFERENCES OCTOBER 1984

Holding the clutch assembly in your fingers, slide Assemble large spacer washer into recess of worm it onto shaft. Assemble pin in hole and slide wheel. Fig. 59. assembly over the pin. Fig. 56.

Assemble worm wheel onto the spline. Fig. 58.

Fig. 58

SERVICE BULLETIN REFERENCES 20.15 OCTOBER 1984

Check to be sure the larger spacer washer is in the recess of the worm wheel. Push both bearings up against each end of transmission assembly. Assemble the shift fork in the groove of the collar. As you place the assembly in the gearcase, guide the lower end of shift fork into pivot hole. Fig. 66.

Fig. 66

Assemble the worm into the gearcase, Turn a few revolutions to check its freedom. Fig. 67.

Fig. 67

NOTE:

Only Lawn-Boy type “A” grease is approved for use in this transmission assembly. If another lubricant is used, it will result in a failure of the transmission.

Fill the lower gearcase with Lawn-Boy type “A” grea’se until it is level with gasket surface. Fig. 68.

Fig. 68

Assemble a new gasket and set cover in place. Fig. 69.

NOTE:

There are two assembly dowels molded into lower case which locate in holes of upper case.

Fig. 69

SERVICE BULLETIN REFERENCES .......................... 20-17 OCTOBER 1984

Assemble the four short bolts into the housings with the heads on top. Assemble the long bolt from the bottom up through the long boss. Assemble the washer, then the nut on the long bolt but don’t tighten until last. Fig. 70.

The correct procedure in tightening the four short bolts and nuts is to use a criss-cross pattern. The required torque on each nut is 35-45 in. Ibs. To obtain equal tightness, tighten one to 20 in. Ibs., then cross over to the opposite corner and tighten to 20 in. Ibs. Tighten the other one on same side to 20 in. Ibs. and the fourth one the same.

Check the rotation of the shaft in both directions. If o.k., use the same procedure in tightening all bolts to 35-45 in. Ibs. Recheck shaft rotation. Fig. 72.

Fig. 70

Run all four nuts on short bolts up snug against housing. Fig. 71.

Fig. 72

Slip the shaft into the self-aligning bearing of the left bracket assembly. A twisting motion will position the transmission into place in the mower housing. Fig. 13.

Fig. 71

Fig. 73

20-18.: SERVICE BULLETIN REFERENCES OCTOBER 1984

Align the transmission with the mounting hole in the mower housing. Insert the shoulder bolt through the mounting hole, install the washer over the threads, and assemble to the transmission.

Fig. 74. Secure with the nut tightened to 35-45 in. Ibs.

Fig. 74

Assemble the right bracket assembly onto the shaft. Install three bolts and start the nuts. Tighten to 142-170 in. Ibs. (12-15 ft. Ibs.)

Fig. 75

SERVICE BULLETIN REFERENCES OCTOBER

Before installing the wheel cover on the shaft, apply Lawn-Boy type “A” grease in the groove. This grease stops dirt and debris from entering the gear area of the wheel. Fig. 76.

Fig. 76

Assemble the washer, the retaining ring and the spacer onto the shaft. Fig. 77.

Fig. 77

Apply Lawn-Boy type “A” grease to the keyseats in the shaft.

Place the small ratchet spring in hole of the shaft. Fig. 78

Fig. 78 .......................................................................................................... 20.19 iR 1984

Place the pinion gear drive key in slot. Fig. 79.

Fig. 79

To install the pinion gear, it will be necessary to push the spring loaded key down while sliding the gear on. Be sure the key stays in place. Assemble the second spacer and retaining ring. After the gear is installed, turn it forward. It should turn freely and you should hear a “clicking” sound which is the key moving over and off the drive shoulder. Turn it backward. The driving shoulder inside the gear should come against the key and stop the rotation. If it doesn’t function as described above you have assembled it backward. Remove the gear very carefully to prevent losing the key and spring and turn the gear end for end and reassemble it. Fig. 80.

Apply a film of Lawn-Boy oil to the wheel bolts. Fig. 81-A. Assemble the wheel and tighten the bolt. Also apply a generous amount of Lawn-Boy “A” grease in the planetary gear of the wheel. Fig. 81-B.

Fig. 81-A Fig. 81-B

Repeat assembly procedures following Fig. 76 through Fig. 81-B on the left wheel.

Fig. 82

Fig. 80


Reassemble handle back on the mower. Install the Attach both springs to the clutch arm and cable hairpin clips. Fig. 83. mounting bracket. Fig. 86.

Fig. 83

Place the “0” ring retainer cup on the square shift fork shaft. The open side must be facing up. Fig. 84.

Fig. 84

Fig. 86

Slide the clutch arm onto the shift fork shaft and press it into place. It will require effort to push it down due to the resistance of the “0” ring. Fig. 87.

Fig. 87 Assemble the “0” ring onto the hub of the clutch arm. Fig. 85.

Fig. 85

SERVICE BULLETIN REFERENCES.... 20.21 OCTOBER 1984

Assemble the clutch cable bracket on the long bolt in the transmission. Make sure the edge of bracket is seated against transmission housing. Assemble the nut and tighten to 35-45 in. Ibs. Fig. 88.

Fig. 88

Turn the clutch arm clockwise and hold it while moving the cable spring in its hole. There should be no tension on it. The hook of the spring should be slightly loose when moving it with your fingers. If it’s too loose, there will be a loss of travel in the clutch arm. This will cause slippage of the clutch assembly resulting in a slipping transmission. If there is tension on this spring, it will cause creepage or forward travel of the mower. Fig. 89.

Pulling the cable down, holding it against the upper part of the handle, place a tie wrap just above the joint of the lower handle. Pull it tight. The second tie wrap should be placed approximately half way down the lower handle. The third tie wrap should be, positioned at the bottom of the lower handle approximately 2-3 inches from the handle bracket. Fig. 90.

Fig. 90

It requires two 1 / 2 open end wrenches to adjust the clutch. Before making adjustments, move the control handle back and forth 3 or 4 times and check the connection of the cable spring on the arm. If it’s out of adjustment as described (too tight or loose), adjust the two 1/2” nuts at the upper end of the cable. If the spring is too loose, back the upper nut off and run the lower nut up. Check the looseness of the spring when doing this. If the spring is tight, turn the nuts in the opposite direction to loosen. Tighten both nuts and, again, move the control handle back and forth 3 or 4 times. Check to determine that the adjustment did not change. Fig. 91.

Fig. 89

If the cable has been replaced, install new tie wraps.

Fig. 91


To reassemble pulley, washer and speed control spacers, refer to Figures 4 through 10-B

Assemble the belt cover. Fig. 92. Start, run and test the mower for engine speed, carburetor ad-

ping time. Engine speed should be 3100-3300 rpm at high speed and 2400-2600 rpm at low speed. It should run smooth and even and start within two pulls. The blade must stop within three seconds.

justments, transmission operation, and blade stop-

Fig. 92

SERVICE BULLETIN REFERENCES. 20.23 OCTOBER 1984

Documents

26622228 Lawn Boy Service Manual 1950 88 Complete